JPH087779A - Electron gun - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the assembly accuracy of the quadrupole of the 4th grid and prevent the deterioration of characteristics. [Structure] The second part G4B to the fourth part G4D of the fourth grid G4 are provided with non-circular openings 12B to 12D, and the parallel parts 15B to 15D are provided on the outer peripheral side thereof. When assembling the fourth grid G4, the parallel portions 15B to 15D are placed against the linear holding portion 24 of the assembly jig 2 and placed. As a result, the contact length between each of the components G4B to G4D and the sandwiching portion 24 of the assembly jig 2 increases, and each of the components G4B to G4.
It is assembled so that D has a predetermined relative positional relationship.
Therefore, the characteristic deterioration of the quadrupole can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun suitable for application to a color CRT or the like.

[0002]

2. Description of the Related Art In recent years, in order to realize a high resolution color CRT (cathode ray tube), it is required to improve the performance of an electron gun. In order to meet this demand, there is an electron gun that has a quadrupole effect to obtain a good beam spot over the entire screen of a CRT. FIG. 5 shows the structure of an electron gun 1 having an electrostatic quadrupole. Since the electron gun 1 accelerates and focuses the electron beam, the ring-shaped first grid G1 to fifth grid G5 are arranged in a line, and
The convergence plate 11 is arranged at the tip of the grid G5. Each of the grids G1 to G5 and the convergence plate 11 are arranged at a predetermined interval from each other, and the outer peripheral side is fixed by a belt-shaped glass bead (not shown) or the like.

In this electron gun 1, the fourth grid G4 is the first
It is composed of a component G4A to a fifth component G4E. Then, a constant focus voltage FC is supplied to the third component G4C, and the first component G4A, the second component G4B, and the fourth component G4D.
By supplying the variable focus voltage FV to the fifth component G4E, the quadrupole action is performed. As a result, it is possible to perform dynamic focusing and, at the same time, cancel the deflection distortion due to the deflection yoke and obtain good focus characteristics over the entire screen. Then, as shown in FIG. 6, the second component G4B, the third component G4C, and the fourth component G.
The degree of the above-described correction is adjusted by appropriately setting the shapes of the 4D non-circular openings 12B to 12D.

At this time, the relative positional relationship of the non-circular openings 12B to 12D of the parts G4B to G4D is determined,
When the respective components G4B to G4D rotate from predetermined positions in different directions or different angles and the relative positional relationship shifts, unnecessary distortion occurs in the electric field lens, which causes a problem that electron beam focus characteristics deteriorate. To do. That is, it is normal for the non-circular openings 12B to 12D to be arranged so that their central axes X and Y are at right angles as shown in FIG. 7 (A), and as shown in FIG. If the axes X and Y are not at right angles, the characteristics deteriorate.

Conventionally, an assembling jig 2 as shown in FIG. 8 has been used in order to improve the assembling accuracy required to bring the relative positional relationships of the parts G4A to G4E into a normal state. The assembly jig 2 has a receiving portion 21 having a semicircular cross section and an appropriate length in order to mount the respective components G4A to G4E without rattling, and a rectangular parallelepiped projection 22 is provided on the bottom portion thereof. ing.
On the other hand, as shown in FIG. 6, each component G of the fourth grid G4
Part G4 of 4A to G4E in which the relative positional relationship is a problem
B to G4D are provided with notches 13B to 13D which are fitted into the protrusions 22 of the assembly jig 2 with substantially no space. The notches 13B to 13D are designed to be fitted into the projections 22 of the assembly jig 2 at the same time when the parts G4B to G4D are arranged so as to have a predetermined relative positional relationship. In this way, after the components G4A to G4E are placed at the predetermined positions on the receiving portion 21, the bead glass is fixed to the outer peripheral side. In addition, at the time of assembly, the second component G4B and the third component G
The spacer 14 is arranged between 4C and the fourth component G4D.

[0006]

In the conventional electron gun 1 with a built-in electrostatic quadrupole, the characteristics of the electrostatic quadrupole may not be sufficiently exhibited. The main reason for this is that the assembly accuracy of the components that make up the quadrupole is poor, as will be described below. That is, as described above, among the first component G4A to the fifth component G4E of the fourth grid G4, the non-circular opening 1
Second part G4B to fourth part G4D having 2B to 12D
As shown in FIG. 9, the notches 13B to 13D are attached to the assembly jig 2
The non-circular opening 12B-
The 12D relative positional relationship is ensured.

However, in reality, for example, since the non-circular openings 12B, 12D of the second component G4B and the fourth component G4D are vertically long and approach the notches 13B, 13D, the notch 13B is present.
The depth H of ~ 13D cannot be made so large, and as shown in Fig. 10, the corners and corners of the cutouts 13B to 13D and the projection 22 must be chamfered C or punched R even though they are very small for the convenience of processing. Since it is provided, the dimension H1 of the linear portion 23 between the side surfaces of the notches 13B to 13D and the side surface of the projection 22 that abuts on the side surfaces.
Becomes very small.

Therefore, when each of the parts G4B to G4D is placed on the assembly jig 2, the straight line portion 2 may be formed depending on a processing error.
There is a case where 3 is almost lost, and the respective components G4B to G4D rotate from the predetermined positions by different directions and different angles. Then, the relative positional relationship of the non-circular openings 12B to 12D of the respective components G4B to G4D is brought into contact, and the characteristics of the quadrupole deteriorate as described above. In some cases, the focus characteristics may be deteriorated rather than when the quadrupole is not provided. Further, if the linear portion 23 is small in this way, each of the components G4B to G4D becomes unstable, and there is a problem that the assembly work is troublesome and the number of steps increases.

Therefore, the present invention solves the above-mentioned problems, and it is possible to improve the assembly accuracy of the quadrupole to prevent the deterioration of the characteristics and to reduce the number of assembly steps. Is proposed.

[0010]

In order to solve the above problems, in the present invention, in an electron gun having a quadrupole for performing focus correction, the same parallel to the outer peripheral side of all the electrodes of the quadrupole. It is characterized in that a parallel portion is provided along the surface.

[0011]

As shown in FIGS. 1 and 2, in the fourth grid G4 having a quadrupole, the non-circular openings 12B to 12D are formed.
The parallel parts 15B to 15D are provided on the outer peripheral sides of the second component G4B to the fourth component G4D having the. The plane passing through the parallel portions 15B to 15D on the same side is parallel to the plane passing through the parallel portions 15B to 15D on the opposite side.

On the other hand, as shown in FIG. 3, the fourth grid G4
The assembling jig 2 is provided with a receiving portion 21 having a semicircular cross section, and a planar holding portion 24 is provided at the center thereof. And when assembling the fourth grid G4,
Parallel parts 15B to 15 of the second part G4B to the fourth part G4D
The parts G4B to G4D are placed on the receiving part 21 by applying D to the sandwiching part 24. As a result, as shown in FIG. 4, the parts G4B to G4D and the holding part 24 of the assembly jig 2 are in contact with each other with a sufficient length H2, so that the parts G4B to G4D are arranged at predetermined positions without rotating. It Therefore, the relative positional relationship between the non-circular openings 12B to 12D is properly held, and the characteristic deterioration of the quadrupole can be prevented. Also, each part G
Since 4B to G4D are stably placed, the assembling work becomes easy.

[0013]

Next, one embodiment of the electron gun according to the present invention will be described in detail with reference to the drawings. The same parts as those described above are designated by the same reference numerals and detailed description thereof is omitted.

FIG. 1 shows the structure of a fourth grid G4 of an electron gun 1 (FIG. 5) to which the present invention is applied. The fourth grid G4 has an electrostatic quadrupole structure and includes a first component G4A.
~ It is constituted by the fifth component G4E. The first component G4A and the second component G4B are fixed, and the fourth component G4D and the fifth component G4E are also fixed. Second part G4B and fourth part G
4D is provided with vertically long non-circular openings 12B and 12D, and the third component G4C is provided with horizontally long non-circular openings 12C. By arranging these non-circular openings 12B to 12D in a predetermined relative positional relationship, the quadrupole action is normally performed.

On the outer peripheral side of each of the parts G4B, G4D having the vertically long non-circular openings 12B, 12D, as shown in FIG. 2A, the central axis Y in the longitudinal direction of each non-circular opening 12B, 12D. Parallel portions 15B and 15D that are parallel to are provided over a predetermined length. Further, as shown in FIG. 3B, a parallel portion 15C perpendicular to the central axis X in the longitudinal direction of the non-circular opening 12C is provided on the outer peripheral side of the third component G4C having the horizontally long non-circular opening 12C. Has been. Each parallel part 15B to 15D
Are on both sides of each of the parts G4B to G4D, and the planes passing through the parallel portions 15B to 15D on the same side are parallel to the planes passing through the parallel portions 15B to 15D on the opposite side.

When assembling the fourth grid G4, an assembly jig 2 as shown in FIG. 3 is used. This assembly jig 2 has a receiving portion 21 having a semicircular cross section and an appropriate length,
A sandwiching portion 24 extending linearly upward from the middle of the arc is provided in the central portion by a predetermined length L. Holding part 24
Is approximately the same as the width of the parallel portions 15B to 15D. Then, when the fourth grid G4 is assembled, the non-circular opening 12B is formed.
Parts G4B to G4D having .about.12D are arranged between the sandwiching portions 24, and the other parts G4A and G4E are arranged before and after the sandwiching portion 24. At this time, the spacer 14 for maintaining a predetermined space is arranged between the second component G4B to the fourth component G4D.

As shown in FIG. 4, the parallel parts 15B to 15D are provided on the respective parts G4B to G4D having the non-circular openings 12B to 12D and are assembled by the assembly jig 2 having the sandwiching part 24. A straight parallel part 15B
15D contact | abuts on the linear clamping part 24. At this time, by appropriately setting the height of the sandwiching portion 24 and the lengths of the parallel portions 15B to 15D, the contact length H2 can be sufficiently secured and each of the components G4B to G4D is surely arranged at a predetermined position. . This prevents the parts G4B to G4D from rotating in different directions and different angles. Therefore, the non-circular openings 12B to 12D of the respective parts G4B to G4D
Since the central axes X and Y in the longitudinal direction can be arranged at right angles to each other, the quadrupole action is normally performed, and the characteristic deterioration can be prevented.

Further, since the holding portion 24 of the assembling jig 2 and the parts G4B to G4D whose relative positional relationship is determined come into contact with each other to be large, the parts G4B to G4D are placed on the assembling jig 2. It becomes stable when placed on the substrate, and the assembling work is easy and the number of steps can be reduced.

[0019]

As described above, according to the present invention, in an electron gun having a quadrupole for performing focus correction, parallel portions along the same parallel plane are provided on the outer peripheral side of all the electrodes of the quadrupole. It is characterized by that.

Therefore, according to the present invention, the parallel portion provided on the outer peripheral side of the quadrupole is brought into contact with the linear holding portion of the assembly jig having an appropriate length to mount the electrode on the assembly jig. It is possible to increase the contact length between the electrode and the assembly jig by placing the electrode on the substrate. This prevents misalignment and rattling of each electrode, and makes it possible to assemble in a predetermined rotational positional relationship, so that the relative positional relationship of the non-circular openings is in a normal state and the characteristics of the quadrupole are It can prevent deterioration. In addition, since the quadrupole is stable during the assembly, the assembly is easy, and the number of assembly steps can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a fourth grid G4 of an electron gun 1 according to the present invention.

FIG. 2 is a diagram showing shapes of a second component G4B to a fourth component G4D of a fourth grid G4.

FIG. 3 is a diagram illustrating a method of assembling a fourth grid G4.

FIG. 4 is a diagram illustrating an assembled state of second to fourth parts G4B to G4D.

FIG. 5 is a configuration diagram of an electron gun 1 having a general electrostatic quadrupole.

FIG. 6 is a configuration diagram of a conventional fourth grid G4.

FIG. 7 is a diagram showing a relative positional relationship between non-circular openings 12B to 12D.

FIG. 8 is a diagram showing a method of assembling a fourth grid G4 of a conventional example.

FIG. 9 is a diagram showing an assembled state of the second component G4B to the fourth component G4D in the conventional example.

FIG. 10 is a detailed view showing a portion A of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron gun 2 Assembly jig 12B-12D Non-circular opening 13B-13D Notch 15B-15D Parallel part 21 Receiving part 24 Clamping part G4 4th grid G4A 1st part G4B 2nd part G4C 3rd part G4D 4th part G4E 5th part

Claims (1)

[Claims] 1. An electron gun having a quadrupole for performing focus correction, wherein parallel portions along the same parallel plane are provided on the outer peripheral side of all the electrodes of the quadrupole. .