JP3101379U - Cup-shaped electrode bottom shape of cold cathode fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To weld a cup-shaped electrode and a lead wire of a conventional cold-cathode fluorescent lamp by welding a cup-shaped electrode having a flat bottom surface and a lead wire, and it is difficult to weld the electrodes together with the center of the lead wire. It has been a problem that welding is incomplete, welding accuracy is deteriorated, and the yield is reduced.
SOLUTION: According to the present invention, the center of the cup-shaped electrode and the lead wire can be aligned by forming the bottom surface of the cup-shaped electrode into a recess having the same shape as the welded portion at the tip of the lead wire and forming a tapered shape inviting the lead wire tip. The problem can be easily solved.
[Selection] Fig. 6

Description

The present invention relates to a cold cathode fluorescent lamp used for a backlight of a liquid crystal display and the like, and more particularly, to a production yield when welding a cup-shaped electrode bottom surface and a lead of a cold cathode fluorescent lamp with a laser or the like. This relates to the shape of the bottom of the cup-shaped electrode for improvement.

FIG. 1 shows the structure of a conventional general cold-cathode fluorescent lamp. A tubular bulb is formed by a glass tube 10 and a glass bead 11 (a pair), and a lead wire 2 (a pair) penetrates the glass bead 11. ) Is sealed. A cup-shaped electrode 1 is attached to a distal end portion of a pair of lead wires 2 in a tubular valve by laser welding or the like. The inside of the tubular bulb is coated with a phosphor coating and sealed with an inert gas and mercury to constitute a cold-cathode fluorescent lamp. The cold-cathode fluorescent lamp is already well-known and will not be described.

FIG. 2 shows a conventional method of mounting a cup-shaped electrode in forming the structure of the cold-cathode fluorescent lamp described above, wherein a lead wire of the cold-cathode fluorescent lamp is provided on the bottom surface of the cup-shaped electrode 1 formed by drawing a metal plate. The tip of No. 2 is pressed with a laser from inside the cup and welded by resistance welding.

FIG. 3 shows a non-defective product when the cup-shaped electrode 1 and the lead wire 2 are exactly at the center, and the optical axis 20 of the laser is also at the center.

FIG. 4 illustrates a state in which the center of the cup-shaped electrode 1 is not aligned with the center of the lead wire 2 at the time of welding. When laser welding is performed as a welding method, the optical axis 20 of the laser is located at the center of the cup-shaped electrode 1, and When the central axis of the line 2 is deviated, the molten shape 1c is deviated as shown in FIG.

In order to set the lead wire 2 at the center of the cup-shaped electrode 1, a welding device including a jig 20 surrounding the cup-shaped electrode 1 and a jig 21 surrounding the lead wire 2 in FIG. The gap between the bottom surface of the electrode 1 and the glass bead 11 was very narrow, and the production and life of the jig 21 were problematic.

In addition, an inert gas is sealed in the jig in the welded portion to prevent oxidation at the time of welding.

Furthermore, the jig 21 surrounding the lead wire may be welded to the molten shape 1c by laser welding, and it is very difficult to manage the welding power during welding.

In the present invention, as a specific means for solving the above-mentioned conventional problems, as shown in FIG. 6, a concave shape 1a having the same shape as the shape of the welded end of the lead wire 2 is provided at the center of the bottom surface of the cup-shaped electrode 1. This is to solve the conventional problem by forming and forming a tapered portion 1b for guiding the lead wire 2 to a concave surface.

A lead wire 2 is formed on a cup-shaped electrode 1 having a concave shape 1a which is the same as the shape of the welded end of the lead wire 2 at the center of the bottom surface of the cup-shaped electrode 1 and a tapered portion 1b for guiding the lead wire 2 to the concave surface. Is unnecessary, the jig 21 described with reference to FIG. 5 becomes unnecessary, and the welding device can be simplified. In addition, an inert gas atmosphere can be created evenly in the gap between the bottom surface of the cup-shaped electrode 1 and the glass bead 11, stabilizing the welding conditions, and improving the yield and productivity. It gives birth.

The lead wire 2 is pressed against an electrode formed in the center of the bottom surface of the cup-shaped electrode 1 with a concave shape 1a that is the same as the shape of the welded end of the lead wire 2. Align the laser irradiation point to the center of the and weld.

If the electrode material is Nada welding material such as molybdenum, welding strength cannot be maintained unless it is welded to the entire circumference of the lead wire, so it is important to align the laser irradiation point with the center of the lead wire as described above. . Also in the case of resistance welding, good heat transfer can be achieved by adjusting the heat transfer to the center of the cup electrode and the center of the lead wire.

This invention is used for cold cathode fluorescent lamps in general.Especially for backlights of large liquid crystal televisions and the like, long cold cathode fluorescent lamps are required. The material of the lead wire is changing to Nada welding materials such as tungsten and molybdenum, and this idea is extremely important and necessary for improving productivity.

It is a figure explaining the structure of a general cold cathode fluorescent lamp. It is explanatory drawing of the electrode part of a general cold cathode fluorescent lamp. It is explanatory drawing welded correctly. FIG. 5 is an explanatory view in which the center of a cup electrode and a lead wire are welded with displacement. It is a figure explaining the structure of an electrode welding jig. FIG. 4 is a diagram showing the configuration of the cup-shaped electrode and the lead wire of the present invention.

Explanation of reference numerals

1 cup-shaped electrode 1a cup-shaped electrode bottom surface 1b cup-shaped electrode bottom tapered shape 1c cup-shaped electrode bottom surface Welding shape 2 ... Lead wire 10 ... Glass tube 11 ... Glass bead 20 ... Jig surrounding cup 21 ... ... Jig surrounding lead

Claims (1)

  A concave shape is formed on the bottom surface of the cup-shaped electrode of a cold cathode fluorescent lamp, and the bottom shape of the cup-shaped electrode for a cold cathode tube for the purpose of satisfying welding accuracy with a lead wire

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