JPS63184244A - Electrode for electron gun and its manufacture - Google Patents

Abstract

PURPOSE:To restrict fluidization of an extra thick part in a direction in which a dent is generated and hence to improve precision for recessed part shaping by forming a groove part at least on a side of vertical deflection corresponding to a periphery of the recessed part and locking this groove part to form said recessed part. CONSTITUTION:A second grid electrode 20 has a slit-shaped recessed part 22 formed on the peripheral part of an electron beam aperture 21 and it has an annular groove part 24 and a projecting part 25 around the recessed part 22 on a recessed part formation surface 23. Thus, when the annular groove part 24 is formed in advance and this groove part 24 is locked to perform a coining process for the recessed part 22, fluidization of an extra thick part in a direction in which a dent is generated can be remarkably restricted upon the formation of the recessed part, and the fluidization of the extra thick part can be centralized in a direction in which the diameter of the lower hole is reduced. Hence, losses can be prevented from being generated and the recessed part can be formed with uniform and high precision for its shaping.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrode for an electron gun of an in-line color cathode ray tube and a method for molding the same, and particularly an electrode and a method for molding the same suitable for improving focus around the screen. Regarding.

[Conventional technology]

Conventionally, as an electron gun for the purpose of improving the focus around the screen of a color cathode ray tube, for example, Japanese Patent Application Laid-Open No. 59-157
The one shown in Japanese Patent No. 936 is known. This structure is
As shown in FIG. 3, a slit-shaped recess 3 is provided in the periphery of the electron beam passing hole 2 of the second grid electrode 1, and the plate thickness of the periphery of the hole 2 is adjusted in the vertical deflection direction (X direction). thick,
The electron beam is made thinner in the horizontal deflection direction (X direction) by I, thereby reducing the divergence angle of the electron beam in the vertical deflection direction (X direction). In addition, in the figure, 4 indicates a ring-shaped protrusion.

To form the recess 3, coining processing using a press V is generally used. For example, Tokuko Sho 40-455
Publication No. 0 is mentioned.

When molding the electrode 1 shown in Fig. 3,
As shown in Japanese Patent Application No. 50, for the purpose of reducing the coining processing force, first, as shown in FIG. 4, a prepared hole 5 for absorbing excess thickness is provided in the relevant portion of the electron beam passage hole 2. Next, as shown in FIG. 5, the recess 3 is formed on the recess forming surface 61 around the pilot hole 5 for absorbing excess thickness by coining. As a result, the excess thickness absorbing pilot hole 5 becomes smaller by 1, as indicated by number 7. Thereafter, a predetermined electron beam passage hole 21 is formed in the portion of the pilot hole 7 for absorbing excess thickness.

[Problem that the invention seeks to solve]

In the above-mentioned prior art, as shown in FIG. Flowing in each direction. At this time, the flow 9 in the direction of the protrusion 4
is absorbed by the deformation shown by the broken line 10, but due to this flow 9, the opening 11i of the recess 3 has an irregular roundness around the circumference.

This causes so-called sink marks. The size of this sink mark becomes irregular around the recess 3, resulting in variations in the accuracy of the recess shape. In order to create a step difference in the recess 3 near the electron beam passing hole 2 shown in FIG. 3F, the shape in the vertical deflection direction (y direction) near the hole 2 is important.

As described above, this causes variations in the precision of the shape of the concave portion in the vertical deflection direction (y direction), and therefore there is a problem that uniform performance cannot be obtained even in the focusing of color cathode ray tubes.

An object of the present invention is to provide an electrode for an electron gun that prevents the occurrence of sink marks and has a highly uniform concave shape precision, and a method for forming the same.

[Means for solving problems]

The above object is achieved by providing a groove on at least the vertical deflection direction side around the recess on the recess forming surface.

[Effect]

At least on the vertical deflection direction side corresponding to the periphery of the recess formed on the recess formation surface (if a groove is provided in advance and the groove is restrained and the recess is coined, the excess thickness in the direction of sinkage generation when the recess is formed) Since the flow of is restricted, sink marks do not occur, and the concave shape can be formed with uniform and high accuracy in the vertical deflection direction (y direction).

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. Second
The grid electrode 20 is arranged around the electron beam passage hole 21 (
It has a slit-shaped recess 22, and an annular groove 24 and a protrusion 25 are provided around the recess 22 on the recess forming surface 23.

The second grid electrode 20 having such a shape is manufactured by the steps shown in FIG. First, as shown in FIG. 11), a prepared hole 26 for absorbing excess thickness is provided in the corresponding part of the electron beam passage hole 21. Next, as shown in the figure (+), the recess 2
2 (corresponding portion I) is provided with an annular groove 24.

The depth of the annular groove 24 is preferably approximately the same as that of the recess 22, and a V-shaped cross section is most effective. Next, as shown in the same figure (cl+), the semi-finished product is
7 and the guide 28, and the guide 29 is lowered from above to restrain the annular groove 24. In this state, the punch 30 is lowered to coin the recess 22. As a result, the excess thickness absorbing pilot hole 26 is deformed into a small shape as indicated by 31. Finally, by forming a predetermined electron beam passage hole 21, a second grid electrode 20 shown in FIG. 1 is obtained.

In this way, if the annular groove 24 is provided in advance and the groove 24 is constrained to form the coining of the recess 22, the flow of excess metal in the direction of sink mark generation when forming the recess can be significantly restricted, and the flow of excess metal in the direction of shrinkage of the prepared hole can be significantly restricted. Since the excess metal can be concentrated in the flow, it is possible to prevent the occurrence of sink marks and to form the concave portion with uniform and high accuracy.

In the above embodiment, the groove 24 is provided over the entire circumference of the recess 22, but as described above, it is possible that sink marks will not occur in the vicinity of the recess 22, that is, at the opening of the recess in the vertical deflection direction (y direction). Since it is important, the groove portion 24 may be partially formed on the vertical deflection direction side.

〔Effect of the invention〕

According to the present invention, by providing a groove at least on the vertical deflection direction side corresponding to the periphery of the recess and constraining this groove to form a recess, it is possible to restrict the flow of excess metal in the sink direction, thereby improving the accuracy of the recess shape. The focus quality of color cathode ray tubes also becomes highly uniform.

[Brief explanation of the drawing]

FIG. 1 shows the electron beam passage hole portion of the second grid electrode according to Embodiment 1 of the present invention, ta) is an enlarged front view, and (ta) is an enlarged front view.
b) is a sectional view, and 111 to tel in FIG. 2 are sectional views in FIG. 1.
Cross-sectional view showing an example of a method for forming a grid electrode, No. 3
The figure shows a conventional second grid electrode, lal is a front view,
(bl is a sectional view, FIGS. 4 and 5 show the conventional method of forming the second grid electrode, fal is an enlarged front view, (b
) is a cross-sectional view. 20... Second grid electrode, 21... Electron beam passing hole, 22... Concave portion, 23... Concave portion forming surface, 24... Groove portion. Figure 4 (G) (b) Figure 5 (CI) (b) 11 Amemoto ^ (( p'″

Claims (1)

[Claims] 1. An electrode for an electron gun in which a slit-like recess is provided around the electron beam passage hole, characterized in that a groove is provided at least on the vertical deflection direction side around the recess on the recess formation surface. Electrode for electron gun. 2. In a method for forming an electrode for an electron gun in which a slit-like recess is provided around the electron beam passage hole, a groove is formed at least on the vertical deflection direction side corresponding to the periphery of the recess formed on the recess formation surface, and then the groove is 1. A method for forming an electrode for an electron gun, characterized in that a concave portion is formed by coining by constraining the electrode.