JPS58214254A - Electrode for electron gun - Google Patents

Abstract

PURPOSE:To obtain an electrode for an electron gun with excellent focusing characteristics by making the R part of the external circumference of the root of the central cylindrical section larger on the short side that on the long side, with respect to the principal lens electrode for the in-line type electron gun of a color cathode-ray tube and improving the degree of roundness of the opening at the root of the cylindrical section. CONSTITUTION:As shown in the figure, an electrode 5 is formed by molding a taper 4 at the opening around the internal circumference of the root of cylindrical sections 1a to 1c by press molding work and molding the R part of the external circumference of the root of the cylindrical sections 1a to 1c into a shape whose radius is different in each region. The R part of the external circumference of the root of the cylindrical sections 1a to 1c is formed by making the radius on the long side region 6a of the three cylindrical sections 1a to 1c in the dimension R1, the radius on the short side region 6b of the cylindrical sections 1a and 1c on both sides in the dimension R2, and the radius on the region 6c within the range of almost 90 deg. at the short side (proximity side to other cylindrical sections 1a and 1c) of the central cylindrical section 1b in the dimension R3 so that the radiuses R1, R2, and R3 of the respective regions 6a, 6b, and 6c can satisfy R1<R2<R3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode for an electron gun, and particularly to a main lens electrode for an Innoline type electron gun of a color cathode ray tube.

Conventionally, such a main lens electrode is made into a single flat plate by stretching, ironing, burring, etc.
As shown in the figure, the electrode 3 is formed by integrally molding lens parts 2a, 2b, 2c having three cylindrical parts 1a, lb, and lc in close proximity in an in-line manner. However, the main lens electrode manufactured using the conventional method has the following parts: the adjacent part between each cylindrical part, the cylindrical part on the short side of the main lens electrode, and the cylindrical part on the long side of the main lens electrode. Since the amount of strain during the stretching and ironing processes is different for each part, the plate thickness at the base of each part differs on the circumference, and the roundness of the base of the cylindrical part decreases. However, there was a drawback that focus characteristics deteriorated.

In order to eliminate such drawbacks, the applicant of the present application has applied for an electron gun electrode 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 opening end. This significantly improved the roundness of the cylindrical portion. However, as a result of trial production, electrodes manufactured by this method have a limit of roundness of around 30 μm at most, and the roundness of the tapered part of the central cylindrical part is always It was found that the shape was elliptical.This is thought to be due to the difference in the amount of springback of the material in the vicinity of the cylindrical part and in other parts.

An object of the present invention is to provide an electrode for an electron gun that can improve the roundness of the opening at the base of a cylindrical portion and has excellent focusing characteristics.

Hereinafter, the present invention will be explained with reference to illustrated embodiments.

FIG. 12 shows an embodiment of the electron gun electrode according to the present invention, tal is a plan view, fb) is a cross-sectional view, FIG. 3 is a cross-section of the central cylindrical part, and FIG. 2B is an enlarged cross-sectional view taken along line A-A'm of FIG. 1, and (b) is an enlarged cross-sectional view taken along B-Bi of FIG. As shown in FIG. 1, the formed electrode 3 is given a taper 4 at the inner circumferential opening of the base of the cylindrical portion 1a to the IC as shown in FIG. 2 and as shown in FIG. At the same time, the electrode 5 is formed by molding the outer periphery R portion of the root of the cylindrical portions 13 to IC into a shape with a different radius in each region as described below. The outer periphery R section has three cylindrical sections 1a to 6a on the long side of the IC with a radius R7,
The cylindrical portions 1a on both sides and the area portion 6b on the short side of the IC are set to radius R2, and the short side of the central cylindrical portion 1b (other cylindrical portions 1a,
The radius of the area 6C within a range of approximately 90 degrees on the side adjacent to the IC is R, 1, and the radii R1, R2, and R3 of each area 6a, 6b, and 6c are R, < R, < R, 3. It is formed so as to satisfy the following.

Now, as an example, the neck part of the cathode ray tube is an electrode for 22 mm diameter, and the dimensions of each part are as follows: The inner diameter of the cylindrical part 13 to the IC is 3.9 mm.
mφ, pitch of cylindrical part 1a to IC is 4.75mm, material plate thickness is 0.33m, height of cylindrical part 1a to IC is 2.1■
, for electrodes with wall thicknesses of cylindrical portion 1a to IC of 0°15 mm, R, = 0.05 tm, R2 = 0, 2 van
, R, = 0.35 When molded to fit the cod, the roundness of the cylindrical parts 1a to IC was within 15 to 20 μm.

In this way, the outer periphery R of the base of the central cylindrical portion 1b is formed such that the radius R3 of the short side area 6C is larger than the radius R1 of the long side area 6a, so it is different from the conventional one. (Compared to this, the amount of springback of the material when forming the taper 4 is smaller in the region portion 6C, and the roundness is improved.

FIG. 4 shows an embodiment of a mold structure for molding the electron gun electrode 5 shown in FIG. The taper 4 is formed by a taper portion 11 formed on the punch 10. Furthermore, the radii R1, R2, and R5 of the respective region portions 6a to 6C of the base peripheral portion of the cylindrical portions 1a to IC are R1, R2, and R5, respectively.
The molding is performed by an 8-part 13 formed at the inner diameter portion of the lower end of the die 12 so as to have a radius of R, , R3. In addition, 14
15 is a lower mold knockout, 16 is a lower mold spring, and 17 is an upper mold spring.

In the above embodiment, the cylindrical portions 1a on both sides, the IC
Although the root outer circumferential R portion was formed to be different on the long side and the short side in the above example, if it is made different at least on the central portion 1b, a better effect than the conventional one can be obtained.

As is clear from the above description, according to the present invention (according to this invention), the outer circumference R of the root of the central cylindrical portion is formed such that the short side is larger than the long side.

The roundness of the aperture is improved, and an electrode for an electron gun with excellent focusing characteristics can be obtained.

[Brief explanation of the drawing]

Figure 1 shows a conventional electron gun electrode, (a) is a plan view;
fbl is a cross-sectional view, FIG. 2 is a plan view of the present invention (one embodiment of the electron gun electrode, fa) is a plan view, (bl is a cross-sectional view, FIG. 3 is a cross-section of the central cylindrical part, and tal is Figure 2 (al
Enlarged cross-sectional view taken along line A-A, (bl is B-B in FIG.
4 is a cross-sectional view showing an example of a mold structure for molding the electron gun electrode shown in FIG. 2. FIG. la, 1b, IC...cylindrical part, 5... electrode, 6
a... Area portion on the long side of the three cylindrical parts, 6b...
Area portions on the short side of the cylindrical portions on both sides, 6c... Area portions on the short side of the central cylindrical portion. Agent Patent Attorney Susuki 1) Toshiyuki Figure 1 (G) 0 (b) (1))

Claims (1)

[Claims] In an electron gun electrode in which three cylindrical parts are integrally molded in close proximity to each other in line, the outer periphery 8 of the base of the central cylindrical part is formed so that the short side area is larger than the long side area. Electrode for electron gun.