JP2000113844A - Stem for cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cracks from being generated even if inward or outward concentrated stress is applied to an inner lead, by forming a fillet part into a shape having a long axis extending in the radial direction from a stem central shaft as seen from the stem inner surface. SOLUTION: A fillet part 20 is formed into an elliptic shape taking an inner lead 3 as the center and having its long axis extending in the radial direction from a stem central shaft. When an electron gun structural body is welded to a stem, if the inner lead 3 is bent in order to connect the inner leads 3 to respective electrodes of the electron gun structural body or supporting bodies, stress is concentrated on the roots of the inner leads 3. However, since each inner lead has a mountainshaped and elliptic fillet part 20 for covering the base part of the inner lead 3, deformation stress is not limited inward and outward around the stem center. Therefore, cracks of the fillet parts 20 can be prevented even if the inner lead 3 are bent inward or outward when the inner leads 3 are welded to the electrodes of the electron gun structural body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fillet structure which is improved against breakage of a fillet when welding an electron gun assembly to a cathode ray tube stem.

[0002]

2. Description of the Related Art As shown in FIGS. 3 and 4, a stem for a cathode ray tube used for a color cathode ray tube or the like is provided on an inner surface side of a disk-shaped glass flange 1 on a concentric circumference with respect to an outer periphery of the flange 1. Are formed integrally with each other, and fine wire-shaped inner leads 3 are planted on the respective fillet portions 2, and outer leads 4 are provided on the outer surface side of the flange 1 with respect to each of the inner leads 3. At the same time, the joint between the inner lead 3 and the outer lead 4 is sealed by the flange 1. In addition, an exhaust pipe 5 for exhausting at the time of encapsulation in a later step is provided at a central portion on the outer surface side of the flange 1.

The shape of the fillet portion 2 of the cathode ray tube stem having such a structure is centered on the inner lead 3 as shown in the plan view of the inner surface (front end portion) of the flange 1 in FIG. As a circular shape.

[0004] Here, the role of the stem is the outer lead 4.
From the electrode lead and the drive signal via the inner lead 3 to the G1 electrode 6, G2 electrode 7, G3 electrode 8, G4 electrode 9, cathode 10, and heater 11, for example, as shown in FIG. Voltage supply and signal transmission are performed via the tape 12 and the tape 13.

In order to properly maintain the positional relationship between the electrodes, a support (not shown) provided at the peripheral portion of each electrode is embedded and fixed in the bead glass 14 and assembled into an electron gun assembly. ing. The connection between the inner lead 3 and the electron gun structure is generally performed by welding.

[Problems to be solved by the invention]

However, when the electrodes and the support 12 and the tape 13 of such an electron gun assembly are connected to the inner leads 3 by welding, the inner leads 3 are not brought into contact with other parts. It is necessary to bend or cut the lead 3 and, in some cases, form it into a crank shape. When the inner lead 3 is bent,
Stress is concentrated at the root of the glass, and the glass in the fillet 2 is broken, and the chip is likely to be chipped, and the chipped glass becomes a foreign substance, which adheres to the shadow mask and causes clogging. There was something to do. Then, when an electron gun assembly with a stem is incorporated into an actual color cathode ray tube or the like, the glass fragments enter the holes of the shadow mask, cause clogging, block the electron beam, and inhibit the emission of the phosphor. There was something.

The main reason is that, in a cathode ray tube stem having a mountain-shaped and circular fillet portion 2 covering the base of the inner lead 3, stress is limited in the circumferential direction in which many inner leads 3 are arranged. Since there is no restriction in the inward and outward directions, the inner lead 3 is bent or cut,
When the inner lead 3 is bent in forming into a crank shape, concentrated stress tends to be applied to the fillet portion 2 at the root of the inner lead 3 inward or outward. That is, when the inner lead 3 of the stem is welded inward or outward when the inner lead 3 of the stem is welded to the electrode of the electron gun assembly, the fillet portion 2 is cracked and chipped in a later step.

In addition, a cathode ray tube stem having a circular fillet portion 2 cannot be increased in size due to the limitation of the interval between the fillet portions 2, and the size of the stem in the radial direction from the stem central axis tied to the limit. This is because only the thickness can be obtained and the thickness in the radial direction from the center of the stem is small, so that the mechanical strength in the inward or outward direction is inevitably weak.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a fillet portion formed at the base of a plurality of inner leads planted on a concentric circumference near an outer peripheral portion on the inner surface side of a disk-shaped flange. In the cathode ray tube stem described above, the fillet portion is shaped to have a long axis in a radial direction from a stem central axis when viewed from an inner surface of the stem.

Further, the fillet portion is formed in an elliptical or elliptical shape, and the inner lead is disposed at the center thereof.

4. The stem for a cathode ray tube according to claim 2, wherein said inner lead is disposed at a center of a fillet portion.

In addition, the inner lead is disposed radially outward from the center axis of the stem from the center of the fillet portion.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The same members as those in FIGS. 3 to 5 are denoted by the same reference numerals, and description thereof will be omitted. FIG.
FIG. 1 is a plan view of a cathode ray tube stem according to an embodiment of the present invention, as viewed from the distal end side of an inner lead 3. A different point from a conventional stem is a shape of a fillet portion 20, and as shown in FIG. 3 is formed in an elliptical shape having a major axis in the radial direction from the stem central axis.
The material is generally made of lead-based glass in order to obtain a high degree of vacuum by fusing with the flared portion of the cathode ray tube bulb in a later step.

FIG. 2 shows how the electron gun assembly is connected to the stem having the elliptical fillet portion 20 by welding.
This will be described with reference to a partial side view of the stem and the electron gun assembly.
When welding the electron gun assembly to the stem, when connecting the inner lead 3 of the stem to the electrodes, the support 12 and the tape 13 of the electron gun assembly by welding, the inner lead 3 needs to be formed, To those who do not need them. In the former case, it is necessary to bend the inner lead 3 or to form it into a crank shape b. When the inner lead 3 is bent, stress concentrates on the root of the inner lead 3. Even in the latter case, the inner lead 3 is cut when the inner lead 3 is cut.
The stress may be concentrated at the root of the sheet.

In this case, in a cathode ray tube stem having a mountain-shaped and elliptical fillet portion 20 covering the base of the inner lead 3, the deformation stress is limited in the circumferential direction in which many inner leads 3 are arranged, as in the past. There is no restriction on the deformation stress inward or outward with respect to the stem center.

However, when stress is applied to the inner lead 3 by bending the inner lead 3, shaping it into a crank shape b, or cutting it, the fillet portion 20 at the root of the inner lead 3 is not used. Even if concentrated stress is applied to the inside or the outside, the elliptical fillet portion 20
Since the thickness in this direction is large, the mechanical strength is maintained, and the fillet portion 20 does not crack. That is, when the inner lead 3 is bent inward or outward when the inner lead 3 of the stem is welded to the electrode or the like of the electron gun assembly, it is possible to avoid a crack from entering the fillet portion 20 here.

As described above, according to the present embodiment, even when the inner lead 3 is slightly bent inward or outward when the stem is welded to the electron gun structure, the elliptical fillet portion 20 is formed. The strength against the concentrated stress inward or outward is strong, so that the fillet portion 20 does not suffer from glass chipping or cracking, and does not generate foreign matter in a later step.

Note that, even if the shape of the fillet portion 20 is changed to form an elliptical shape in the radial direction from the central axis of the stem,
The same effect of preventing the glass chipping of the fillet portion 20 as in the above embodiment is exhibited.

Further, in the above-described embodiment, an example has been described in which the inner lead 3 is disposed at the center of the elliptical or oval fillet portion 20, but the present invention is not limited to this, In consideration of the tendency of the bending direction of the inner lead 3 in the above, the inner lead 3 may be disposed radially outward or inward from the center axis of the stem from the center of the fillet portion 20.

[0020]

As described above, according to the present invention, even when concentrated stress is applied to the inner lead inward or outward during the welding of the cathode ray tube stem to the electron gun assembly, the fillet portion is formed. Cracks do not occur.

Further, even if the interval between the fillets (lead interval) is made equal, the strength of the fillet when the inner lead is bent can be enhanced.

[Brief description of the drawings]

FIG. 1 is a plan view of a cathode ray tube stem according to an embodiment of the present invention.

FIG. 2 is a partial side view of an electron gun assembly for explaining stem welding according to the present invention.

FIG. 3 is a perspective view of a conventional cathode ray tube stem.

FIG. 4 is a plan view of the same.

FIG. 5 is a side view showing a connection state between a general cathode ray tube stem and an electron gun assembly.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flange 3 Inner lead 4 Outer lead 5 Exhaust pipe 6 G1 electrode 7 G2 electrode 8 G3 electrode 9 G4 electrode 10 Cathode 12 Support body 13 Tape 14 Exhaust pipe 20 Fillet part

Claims (6)

[Claims] 1. A cathode ray tube stem having a fillet formed at the base of a plurality of inner leads planted concentrically in the vicinity of an outer peripheral portion on the inner surface side of a disc-shaped flange, wherein the fillet is viewed from the inner surface of the stem. A stem for a cathode ray tube, having a shape having a major axis in a radial direction from a stem central axis. 2. The cathode ray tube stem according to claim 1, wherein said fillet portion is formed in an elliptical shape. 3. The stem for a cathode ray tube according to claim 1, wherein said fillet portion is formed in an oval shape. 4. The stem for a cathode ray tube according to claim 2, wherein said inner lead is disposed at a center portion of a fillet portion. 5. The cathode ray tube stem according to claim 2, wherein the inner lead is disposed radially outward from a center axis of the stem from a center of the fillet portion. 6. The stem for a cathode ray tube according to claim 2, wherein the inner lead is disposed radially inward from a center axis of the stem from a center of the fillet portion.