JPH0765717A - Laser welding method - Google Patents

Abstract

PURPOSE:To prevent the occurrence of welding splash when members used in a cathode-ray tube ore welded together. CONSTITUTION:In welding together a first member (IMS5) and a second welding member (STC6), used in a cathode-ray tube, an opening 5a is made in IMS5 in advance. IMS5 having the opening 5a and STC6 are then mutually piled up. Laser beam L is irradiated to a welding position A of IMS5 and STC6 through the opening 5a made in IMS5, for laser welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser welding method for members used in a cathode ray tube. More specifically, the present invention relates to a laser welding method capable of welding members by reducing a welding splash that causes a failure in electrical withstand voltage of a cathode ray tube.

[0002]

2. Description of the Related Art There are many welded parts inside a cathode ray tube. For example, in a Trinitron type color CRT, an internal magnetic shield plate (inner magnetic shield: abbreviated as IMS hereinafter) has a self-temperature correction plate (abbreviated as STC hereinafter) provided on a frame of an aperture grill (color selection mask). ), There are many welding sites such as other electron gun parts.

The IMS is a magnetic shield material applied to suppress the external magnetic field scattering of an electron beam emitted from an electron gun and prevent a phenomenon called geomagnetic drift and an image rotation phenomenon called image rotation. As a material for the IMS, a thin metal plate capable of drawing in an external magnetic field such as geomagnetism is used. For example, as shown in FIG.
Color CR consisting of a glass outer tube consisting of a panel 1 and a funnel 2 and an aperture grill 3 inside it.
When the IMS is attached to T4, a thin metal plate in the shape of a quadrangular pyramid frame is attached to the frame material of the aperture grill 3 by welding as the IMS 5. In this case, the resistance welding method is usually employed as the welding method. More specifically, as shown in FIG. 2 (the top view of FIG. 2A and the sectional view of FIG. 2B), the STC 6 is preliminarily joined to the frame material 3a of the aperture grill as a buffer material for heat during resistance welding. Then, the IMS 5 is overlaid thereon, and the welding portion A is heated and pressed by the electrode rod 8 as shown by the arrow.

[0004]

However, according to the conventional resistance welding as described above, the electrode rod 8 is welded to the welding site A.
Since a shocking pressure is applied to the IMS 5 in a molten state at the time of heating and pressurizing, the welding splash occurs.

On the other hand, when the welding splash is present inside the cathode ray tube, electric charges are concentrated on the welding splash when a high voltage is applied to the inside of the cathode ray tube, so that unnecessary discharge is caused and electrical withstand voltage failure occurs, resulting in a product value. Significantly impaired. Also, during transportation of the cathode ray tube, welding splash due to vibration etc., especially needle-shaped welding splash, may fall into the cathode ray tube from the welding site, but even if the dropped welding splash adheres to the electrode surface of the electron gun. Similar phenomenon occurs.

Therefore, conventionally, when welding members used in the cathode ray tube to each other, various methods have been taken to reduce the welding splash. For example, the amount of welding splash generated varies depending on the thickness and type of the metal member to be welded, the stability of the current during resistance welding, the pressure condition of the electrode rod, etc. The conditions for resistance welding have been set. However, it is very difficult to determine such condition setting, and it is difficult to maintain such a condition in terms of facility management, and it is practically impossible to eliminate the welding splash.

Further, in order to reduce welding splash, the electrode rod and its peripheral portion are also cooled. However, this method has a problem that the cooling equipment becomes large-scale.

In order to avoid the problem of welding splash, there is also a method of stopping the members to be joined with a clip without welding, but it is difficult to join them with high positional accuracy, and the joining cost is high. There are also problems.

The present invention is intended to solve the above-mentioned problems of the prior art, and an object thereof is to prevent generation of welding splash when welding members used in a cathode ray tube. I am trying.

[0010]

The inventor has found that the members used in the cathode ray tube are welded to each other by laser welding, and in that case, one member is provided with an opening to join the members to be joined. It was found that the generation of welding splash can be remarkably reduced by directly irradiating the laser beam on the surface of the steel, and the present invention has been completed.

That is, the present invention relates to a welding method of a first member and a second member used in a cathode ray tube, wherein an opening is provided in advance in the first member and then an opening is provided. A laser welding method, characterized in that the first member and the second member are overlapped with each other, and a laser beam is applied to a welding site of the first member and the second member through an opening provided in the first member I will provide a.

[0012]

According to the method of the present invention, laser welding is performed when the first member and the second member used in the cathode ray tube are joined by welding, so that the welding site is heated more intensively than resistance welding. It becomes possible to do. In this case, since the first member is provided with an opening in advance and the laser light is irradiated through the opening, the laser light is applied to the first member and the second member.
It is possible to directly irradiate the welded part of the member and heat the welded part more intensively and efficiently. Therefore, the weldability is improved.

Further, it is possible to prevent unnecessary heating of a portion other than the welded portion, and since the electrode rod does not pressurize the welded portion as in the case of resistance welding, the occurrence of welding splash is significantly suppressed. It becomes possible to do.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be specifically described below with reference to the drawings. In each drawing, the same reference numerals represent the same or equivalent constituent elements.

FIG. 1 illustrates an IM according to the method of the present invention.
It is explanatory drawing at the time of welding S5 and STC6 (the same figure (a) top view, the same figure (b) sectional view). In this embodiment, the STC (thickness of several millimeters) 6 is bonded to the frame material 3a of the aperture grill in advance, and the opening 5a is formed thereon.
It shows a method of stacking an IMS (thickness of about 1.5 mm) 5 provided with, irradiating a laser beam L, and performing laser welding.

As described above, according to the present invention, the opening 5a is first provided in the IMS 5 before the laser light irradiation. here,
The size and shape of the opening 5a are not particularly limited as long as the laser light L can pass therethrough. For example, a circular shape having a diameter of about 5 mm may be used. The method of forming the opening 5a can be performed by punching or the like. However, if there is a burr in the punching hole, electric charge concentrates on the burr, which causes poor electrical breakdown voltage. Therefore, chamfering is performed after the punching. It is preferable.

After the IMS 5 having the opening 5a is superposed on the STC 6, the laser beam L is directly applied to the joining portion A through the opening 5a. This allows IMS5 and S
The joint portion A with the TC 6 is intensively and efficiently heated.

As the type of laser light L used for such laser welding, a YAG laser, a GAS laser, a carbonic acid laser, a free electron laser or the like can be used.

There are no particular restrictions on the type of welded member to which the method of the present invention can be applied. For example, as shown in FIG.
When welding MS5 and STC6, a decarbonized material (mild steel) or the like can be used as the IMS5.
For 6, SUS304, 22NI or the like can be used. Further, depending on the irradiation conditions of the laser light L, the heat during welding hardly reaches the aperture grille, so the IMS 5 may be directly welded to the frame member 3a of the aperture grille without passing through the STC 6. In this case, the material of the frame material 3a of the aperture grill is not particularly limited, and the same material as the conventional example can be used, for example, the frame material made of SUS304, SCM415 or the like can be used.

In the cathode ray tube, in addition to the IMS 5 and the STC 6 or the frame material 3a of the aperture grill, there are many members that are welded to each other. For example, the aperture grill holder A (D) (material: bimetal) and the aperture grill spring. Joining with A (material: SUS301), aperture grill holder BC (material: SUS)
430) and aperture grill spring (material: 42
0J2), HV connector (material: SUS30)
4) and frame material (material: SUS403, SUS415)
Etc.), damper spring (material: SUS63)
1) and frame material (material: SUS403), getter rest (material: SUS304) and getter ring (material: SUS304), electron gun stem inner lead and G4 (material: SUS304), Joining stem inner lead of electron gun and IBR (material: Inconel), joining stem inner lead of electron gun and G2 lead (material: SUS), stem inner lead of electron gun and G1 pin (material: SUS304) Joining the
Joining of stem inner lead of electron gun and heater lead (material: quasi-Ni), joining of stem inner lead of electron gun and cathode (material: SUS304), stem inner lead of electron gun and electrode (non-magnetic) (material) : NM,
SUS), electron gun stem inner lead and H
There are joining with a V spring (material: Inconel), joining with a stem inner lead of an electron gun and an HV connector (material: Inconel), and these can also be suitably welded by the method of the present invention.

[0021]

According to the present invention, it is possible to prevent the generation of welding splash when welding the members used in the cathode ray tube.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of laser welding of IMS and STC according to an embodiment.

FIG. 2 is an explanatory view of conventional resistance welding between IMS and STC.

FIG. 3 is an explanatory diagram of a color CRT equipped with an IMS.

[Explanation of symbols]

 1 Panel 2 Funnel 3 Aperture Grill 3a Frame Material for Aperture Grill 4 CRT 5 IMS 5a Opening 6 STC A Welding site L Laser light

Claims (2)

[Claims] 1. A method for welding a first member and a second member used in a cathode ray tube, the first member comprising an opening provided in advance in the first member and then an opening provided in the first member. And a second member are overlapped with each other, and a laser beam is applied to a welding portion of the first member and the second member through an opening provided in the first member. 2. The laser welding method according to claim 1, wherein the first member is an internal magnetic shield plate, and the second member is a self-temperature correction plate provided on the frame of the aperture grill.