JPH0443373B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an electrode for an electron gun, and more particularly to a main lens electrode for an in-line electron gun of a color cathode ray tube.

[Background of the invention]

Conventionally, such a main lens electrode has been made into three cylindrical parts 1 by performing stretching, ironing, burring, etc. on a single flat plate as shown in FIG.
Lens parts 2a, 2b, 2 having a, 1b, 1c
c are integrally molded in close proximity in line. However, the main lens electrode 3 manufactured by this method has the following parts: the proximate portion between each cylindrical portion 1a to 1c, the cylindrical root portion on the short side of the main lens electrode 3, and the long side of the main lens electrode 3. Since the amount of strain at the cylindrical root portion differs when subjected to elongation processing and ironing processing, the plate thickness of the root portion of each portion differs on the circumference, and the cylindrical portions 1a to 1
There was a drawback that the roundness of the root part of c was reduced and the focus characteristic was deteriorated.

In order to eliminate such drawbacks, the applicant of the present application has applied for an electrode for an electron gun in which a tapered part is formed in the opening at the base of the cylindrical part, the inner diameter of which increases toward the end of the opening. However, in electrodes manufactured using this method, the amount of springback of the material differs between the part near the base of the cylinder and the other parts, and the roundness of the taper part of the central cylinder always has an elliptical shape on the long side of the electrode. It turned out to be.

Therefore, in order to further eliminate the above-mentioned drawbacks, the applicant of the present application has applied for an electrode in which the outer circumference R of the central cylindrical root is made larger in the vicinity of the cylindrical root and smaller in the other parts, taking into account the amount of spring back in the vicinity of the cylindrical root of the electrode. . However, as a result of trial production, the electrode manufactured by this method had a limit of circularity of 15 to 20 μm. Further, the processing of the R portion around the three in-line adjacent holes at the tip of the shaping die used in this molding was done by hand, and was difficult to reproduce.

[Purpose of the invention]

An object of the present invention is to provide an electrode for an electron gun that improves the roundness of the opening at the base of the cylinder and has excellent focus characteristics.

[Summary of the Invention] The present invention is characterized in that a circular annular groove is formed on the outer periphery of the root of the cylindrical portion at both ends, and the region on the long side is made smaller than the region on the short side at the outer periphery of the root of the central cylindrical portion. It is characterized by forming annular grooves having different diameters and having a large groove width.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. Note that the same or equivalent parts as in FIG. 1 will be described with the same reference numerals. As shown in FIG. 2, a taper 4 is formed on the electrode 3 formed as shown in FIG. ~1
Annular grooves 5a, 5b,
5c is molded to form an electrode 6. Here, the annular grooves 5a, 5c formed on the outer peripheries of the bases of the cylindrical portions 1a, 1c at both ends are formed in a circular shape. The annular groove 5b formed on the outer periphery of the base of the central cylindrical portion 1b is formed in a shape with a different diameter such that the longer side area has a larger groove width than the shorter side area.

Now, as an example, the cathode ray tube neck diameter is 22mmφ.
The dimensions of the cylindrical parts 1a to 1c are 3.9 mm in inner diameter, 0.15 mm in wall thickness, 2.1 mm in height, and 4.75 mm in pitch. The annular grooves 5a and 5c have an outer diameter of 4.6 mmφ,
The central annular groove 5c was formed with an outer diameter of 5.1 mm on the long side and a 4.6 mm outer diameter on the short side, each having a depth of 0.1 mm. The roundness was less than 15μm.

In this way, the annular groove 5b on the outer periphery of the root of the central cylindrical portion 1b is formed so that the region on the long side is larger than the region on the short side. The roundness deformation on the long side side of the root opening of 1b can be restrained, and the roundness is improved.

Such an electrode 6 for an electron gun can be easily molded using the mold structure shown in FIG. That is, the taper 4 is the same as the taper 1 formed on the punch 10.
Molded by 0a. Cylindrical parts 1a, 1 at both ends
The annular grooves 5a, 5c on the outer periphery of the base of c are connected to the central cylindrical portion 1b by circular annular protrusions 11a, 11c formed at the tip of the shaping die 11 shown in FIGS. 3 and 4. An annular groove 5 on the outer periphery of the base of
b are respectively formed by annular protrusions 11b having different diameters formed at the tip of the shaping die 11. Note that 12 is a lower mold knockout, 13 is an upper mold knockout, 14 is a lower mold spring, and 15 is an upper mold spring.

〔Effect of the invention〕

According to the present invention, an annular groove having a different diameter is formed on the outer periphery of the root of the central cylindrical portion, and the groove width on the long side is larger than that on the short side. The roundness deformation on the side side is restrained, the roundness of the root opening of the cylindrical portion is improved, and an electrode for an electron gun with excellent focus characteristics is obtained.

[Brief explanation of drawings]

FIG. 1 shows a conventional electron gun electrode, in which a is a plan view and b is a cross-sectional view. FIG. 2 is an embodiment of the electron gun electrode according to the present invention, in which a is a plan view and b is a cross-sectional view. Figure 3 is a sectional view showing an example of a mold structure for shaping the electron gun electrode shown in Figure 2;
The figure shows an enlarged view of the tip of the shaping die shown in FIG. 3, where a is a cross-sectional view and b is a bottom view. 1a, 1b, 1c...cylindrical part, 5a, 5b, 5
c... Annular groove, 6... Electron gun electrode.

Claims (1)

[Claims] 1. In an electron gun electrode in which three cylindrical parts are integrally molded in close proximity in line, a circular annular groove is formed on the outer periphery of the root of the cylindrical parts at both ends, and a circular groove is formed on the outer periphery of the root of the central cylindrical part. An electrode for an electron gun, in which an annular groove with a different diameter is formed in a region on the long side and a groove width larger than that in the region on the short side.