JPH0664988B2 - Method of manufacturing electron gun electrode - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electron gun electrode, and more particularly, to an in-line type electron gun mounted on a shadow mask type color picture tube for injecting three electron beams in a row. The present invention relates to a method of manufacturing an electrode that forms a main lens portion.

[Background of the Invention]

Conventionally, in the electron gun for color picture tube of the type described above,
As an improved resolution, for example, JP-A-57-103246
As shown in the publication, opposing main lens electrodes have peripheral rims on their respective opposing end sides, and an elliptical lens space is formed by a recess between the peripheral rim and an aperture forming surface formed by retracting. The structure is known.

In this structure, the potential on the electrode side facing the ellipsoidal lens space deeply penetrates to form a lens with a large diameter, and spherical aberration can be reduced, so that the electron beam spot diameter is reduced. It is effective for doing.

However, this structure does not necessarily consider the importance of press working accuracy of the main lens electrode part and the problem of manufacturing cost. That is, to describe the processing accuracy of the electrode parts, the recess formed on the facing surface side becomes the large-diameter lens forming area, and the oval contour accuracy (shape accuracy) is the shape of the beam spot on the fluorescent surface. The shape of the beam spot becomes more uniform as the machining accuracy is higher. Therefore, in order to improve the contour accuracy of the recess, it becomes insufficient depending on the conventional general press working method, and due to the variation of the working accuracy, the beam spot shape lacks uniformity, This causes variations in color picture tube resolution.

This will be further described with reference to FIG. FIG. 1 shows a working example of an electrode press part having the above-mentioned recess which is generally used in the past. First, a disc-shaped blank 1 is punched as shown in FIG. Next, as shown in FIG. 3B, a recess 2 having an oval outline and a predetermined depth is formed by overhanging. Next, as shown in FIG. 3C, the container portion 3 is formed by drawing into a predetermined container-shaped dimension. After that, as shown in FIG. 3D, the opening forming surface of the recess 2 is punched to form the opening 4, and the electrode component is completed.

However, in such a processing method, when the container portion 3 is formed by drawing as shown in FIG. 3C, the contour dimension and the depth dimension of the recess 2 formed in advance vary due to the processing force. To do. Therefore, in FIG. 2B, it is necessary to form the recess 2 in consideration of the variation. However,
The drawing force largely depends on the lubrication state in the mold and is not always stable. For this reason, the expectation for the above variation corresponds to an average, and the effect for obtaining a uniform contour size and the depth of the recess cannot be sufficiently obtained.

[Object of the Invention]

An object of the present invention is to provide a method for manufacturing an electron gun electrode, which can improve the resolution of a color picture tube and prevent the fluctuation by improving the precision of press working of a main lens electrode.

[Outline of Invention]

According to one embodiment of the present invention, after the container portion is formed so that the tip portion has a conical shape, the conical portion is inverted and compressed in the container portion direction to secure the shape of the recess. It is possible to improve the shape accuracy of the place and stabilize it.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 shows an example of a main lens electrode to which the present invention is applied. The G ₃ lower electrode 10 and the G ₃ upper electrode 11 are integrally formed, and the G ₄ electrode 12 is fixed to the shield cup 13. The G ₃ upper electrode 11 and the G ₄ electrode 12 are opposed to each other with a gap g, and both electrodes 11 and 12 have an oval shape having the same horizontal length H and vertical length V on the facing surface side. Opening part (recess) 11
Opening forming surfaces 11b and 12b are formed so as to have a and 12a, respectively. The depth of the oval openings 11a of G ₃ upper electrode 11 is the depth of the oval openings 12a of l _1, G ₄ electrode 12 is displaced with l _2, it is formed on the l _1> l ₂ ing. In addition, the surface where the aperture is formed
Openings 11c and 12c are formed in 11b and 12b, respectively.

Next, the processing method of the G ₃ upper electrode 11 and the G ₄ electrode 12 will be described in the third step.
It will be described with reference to the drawings. First, as shown in FIG. 3A, a blank 20 having a disc shape is punched. Next, as shown in FIG. 3B, the container portion 22 is formed by drawing so that the tip portion becomes the cone portion 21. Then, as shown in FIG.
The general shape of the recess 23 is formed by compressing the inward direction of the container portion 22 and inverting it. Thereafter, as shown in FIG. 3D, the recess 23 is formed so as to have a predetermined contour size and depth.
Is shaped to form a predetermined recess 24. Next, as shown in FIG. 7E, the opening forming surface 25 of the recess 24 is punched to form an opening 26, thus completing the container-shaped electrode.

In this way, after the outer shape of the container-shaped electrode is formed (see (c) in the figure), the shape of the recess 24 is completed (see (d) in the figure).
Therefore, the fluctuation of the recess shape, which has been a problem in the conventional processing method, does not occur. For this reason, it is not necessary to anticipate the molding dimensions in advance, so the accuracy of the press work of the recess 24 is improved,
Also, stable dimensions can be obtained.

〔The invention's effect〕

As is clear from the above description, according to the present invention, since the press working accuracy and the dimensional stability of the recess of the counter electrode forming the large aperture lens are improved, the variation of the resolution of the color cathode ray tube is prevented. .

[Brief description of drawings]

1 (a) to 1 (d) are process drawings showing a conventional method for manufacturing an electron gun electrode, FIG. 2 shows an example of a main lens electrode to which the present invention is applied, and (a) is a tube axis direction and 3 FIG. 3A is a cross-sectional view taken along the array direction of the electron beams of the book, FIG. 3B is a cross-sectional view taken along the vertical direction, and FIG. 3C is a front view of the G ₃ upper electrode viewed from the G ₄ electrode side. 7A to 7E are process diagrams showing an embodiment of the method for manufacturing an electron gun electrode according to the present invention. 21 …… Conical part, 22 …… Container part, 23,24 …… Recess, 25 …… Opening surface.

Claims (1)

[Claims] 1. An oval-shaped lens space is formed by facing each other and having peripheral rims on the respective opposite end sides, and a recess between the peripheral rim and the aperture forming surface retracted from the facing end. In the method of manufacturing an electron gun electrode, after forming a container part so that a tip part has a cone shape, the cone part is reversely compressed in the container part inward direction and a peripheral rim is retracted and an aperture forming surface is formed. A method of manufacturing an electron gun electrode, which comprises forming a recess.