JPH0756778B2 - Mesh electrode and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a mesh electrode in which deformation of a dome-shaped mesh is prevented, and a method for manufacturing the same.

[Background Art and its Problems] Generally, in an electrostatic deflection type cathode ray tube for observation, a mesh electrode is arranged in front of a deflection electrode of an electron gun in order to improve brightness and deflection sensitivity. Particularly, in order to improve the deflection sensitivity over the entire surface in the X-axis direction and the Y-axis direction, a mesh electrode in which a peripheral edge of a dome-shaped mesh is supported and fixed by a mesh ring is used.

This type of mesh electrode has been conventionally used in FIGS. 3 (a) and 3 (b).
After joining the peripheral portion of the flat mesh 1 and the first mesh ring 3 by the cold pressure welding method as shown in FIG.
A thin second mesh ring 2 having a thickness of 0.1 mm is fixed to the mesh ring 3 by spot welding. In the figure,
The cross mark indicates the welding location. Also, A indicates a flat surface, and the flatness is
It is within 0.02 mm. After that, the mesh 1 is formed into a dome shape by hot or warm forming. At this time, the mesh ring 2 does not directly contribute to improving the deformation strength of the mesh, but has a function as a guide for making the shape of the mesh uniform when forming the mesh into a dome shape. After that, the dome-shaped mesh electrode is shipped to the process of assembling the electron tube.

However, there is a problem that a part of the dome-shaped mesh 1 is deformed into a concave shape during the transportation of the mesh electrode or the assembly process of the electron tube. If this deformed mesh electrode is used as it is in an electron tube, the tube characteristics will be NG (there will be a serious failure among the tube failures). The cause of the above is the second
It is considered that the mesh ring 2 is deformed and the distortion is caused by welding. Further, it is considered that the strength of the first mesh ring 3 is insufficient.

[Object of the Invention] An object of the present invention is to provide a mesh electrode in which deformation of a dome-shaped mesh is prevented and a method for manufacturing the same.

[Summary of the Invention] The present invention includes a mesh ring and a dome-shaped mesh whose peripheral portion is pressure-welded to the mesh ring, and the mesh ring is formed so as to have a cross section inclined to the convex portion side of the dome-shaped mesh. It is a mesh electrode characterized by being formed by contact processing.

Further, the present invention provides a method of manufacturing a mesh electrode, comprising a step of supporting and fixing to a flat mesh and a mesh ring, and a step of forming the mesh into a dome shape, wherein the step of supporting and fixing the mesh is a peripheral edge of the mesh by pressure welding. The method for producing a mesh electrode is characterized in that the portion and the mesh ring are joined together and the mesh ring is shaped so as to have a cross section inclined to the mesh side.

[Embodiment of the Invention] The mesh electrode of the present invention is configured as shown in FIGS. 1 (a) and 1 (b), and the peripheral portion of the dome-shaped mesh 4 is
It is supported and fixed to the mesh ring 5. In this case, in the present invention, the mesh ring 5 has an outer peripheral portion 5a having a convex portion of the dome-shaped mesh 4 as is apparent from FIG. 1 (b) showing an enlarged portion a of FIG. Using a molding die not shown so as to have a slanted section on the part side, it is molded by pressure welding, for example cold pressure welding, and the inclination angle θ
Is set in the range of 30 'to 3 °.

A method of manufacturing such a mesh electrode includes a step of supporting and fixing the mesh and the mesh ring, and a step of forming the mesh into a dome shape. Since the step of forming the mesh into a dome shape is the same as in the conventional example, detailed description will be omitted. Then, in the step of supporting and fixing the mesh and the mesh ring, the mesh 4 and the mesh ring 5 are joined by cold pressure welding, and at the same time, the mesh ring 5 is plastically worked and the mesh ring 5 is inclined to the mesh 4 side 5a. To be molded. The peripheral portion 4a of the mesh 4 is arranged along the pressure contact surface 5b with the ring 5.
As a result, the mechanical strength of the mesh ring 5 was improved by work hardening, and the deformation strength of the mesh was improved 2 to 4 times. At this time, it goes without saying that the inclination angle θ is set in the range of 30 ′ to 3 °.

According to this embodiment, the following excellent effects can be obtained.

(1) Since the mesh ring 5 is formed by pressure welding so that the outer peripheral portion 5a has a slanted cross section on the convex side of the dome-shaped mesh 4, the mechanical strength of the mesh ring 5 is improved. , The deformation strength of the mesh is
It is 2 to 4 times that of a conventional dome mesh electrode using a flat mesh ring.

(2) Conventionally, the dome molding could not be performed without the mesh ring 2 in FIG. 3, but in the present invention, the dome molding can be molded by eliminating the mesh ring 2 and improving the molding jig. It was

(3) Due to the same as above, conventional welding work was abolished, and
Direct materials as parts are also reduced, labor is reduced in terms of cost,
Cost reduction can be achieved.

(4) Since the mesh deformation is largely due to the welding variation of the mesh ring 2, the yield is improved by eliminating the mesh ring 2.

The measuring method of the mesh deformation strength is shown in FIG.
It shows in (b). In the measurement, the dome-shaped product, that is, the mesh electrode 6 is placed on the V block 7,
A weight W is applied to the center of the mesh electrode 6 . At that time,
A concave deformation occurs in a part of the dome-shaped mesh 4, and the value at this time is defined as the mesh deformation strength.

The present invention is applicable not only to the electrostatic deflection type cathode ray tube but also to electron tubes using mesh such as an image pickup tube or a photoelectric tube and the like.

[Effect of the Invention] According to the present invention, the mechanical strength of the mesh ring is improved, and the deformation strength of the mesh is improved to 2 to 4 times that of the conventional one.

[Brief description of drawings]

1 (a) and 1 (b) are side views including a partial cross-section showing a mesh electrode according to an embodiment of the present invention, and enlarged cross-sectional views showing a part of this side view in an enlarged manner. a),
(B) is a plan view and a sectional view showing a mesh deformation strength measuring method, and FIGS. 3 (a) and 3 (b) are a plan view and a sectional view showing a conventional mesh electrode. 4 ... dome mesh, 5 ... mesh ring

Claims (2)

[Claims] 1. A mesh ring, and a dome-shaped mesh whose peripheral portion is pressed against the mesh ring, wherein the mesh ring has a cross section which is inclined toward the convex portion of the dome-shaped mesh by the pressing. A mesh electrode characterized by being molded into. 2. A method of manufacturing a mesh electrode, comprising: a step of supporting and fixing a flat mesh on a mesh ring; and a step of forming the mesh into a dome shape, wherein the step of supporting and fixing the mesh is performed by pressure welding. A method for producing a mesh electrode, comprising joining a peripheral edge portion and the mesh ring and molding the mesh ring so as to have a cross section inclined to the mesh side.