JP2005025976A - Sealing lead wire and cold cathode fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing lead wire having an external lead wire and causing no cost increase, which can be connected to a sealing material for hard glass, and is excellent in corrosion resistance and workability, and a cold cathode fluorescent lamp having this lead wire. <P>SOLUTION: This sealing lead wire 3 is equipped with the sealing material 4 comprising kovar, tungsten, or molybdenum, and the external lead wire 5 connected to the outside end of the sealing material 4, in which a copper layer 5b is coated on the surface of an ion-nickel core wire 5a, and a nickel layer 5c is coated on the copper layer 5b. Since the lead wire in which the copper layer 5b and the nickel layer 5c are coated on the ion-nickel core wire 5a is used for the external lead wire 5 connected to the outside end of the sealing material 4, this sealing lead wire has no problem in welded connection, excellent corrosion resistance and excellent workability, and its cost can be suppressed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sealing lead wire used for a tube product such as a cold cathode discharge lamp and a cold cathode fluorescent lamp using the lead wire.
[0002]
[Prior art]
In recent years, small personal computers and televisions using liquid crystal display devices (hereinafter abbreviated as LCDs) have been promoted to be thinner and have higher luminance. As a small fluorescent lamp used in a backlight device for illuminating the LCD, a cold cathode fluorescent lamp that is easy to downsize and excellent in life characteristics is often used.
[0003]
Since the cold cathode fluorescent lamp has a cold cathode electrode, it is possible to reduce the bulb diameter, and an extremely small lamp having an bulb inner diameter of 12 mm or less, for example, 5 mm or less has been developed. As the cold cathode fluorescent lamp becomes smaller and has higher output, the glass constituting the bulb tends to use hard glass such as quartz glass or borosilicate glass rather than soft glass. As described above, as a lead wire for sealing a cold cathode fluorescent lamp using hard glass as a bulb, Kovar (iron, nickel, cobalt alloy), tungsten, tantalum, niobium or molybdenum was used as a sealing material. The thing is proposed (for example, refer patent document 1).
[0004]
In this prior art, a nickel wire is used for the external lead wire connected to the outer end portion of the hard glass sealing material.
[0005]
Moreover, as a sealing member for a soft glass bulb, sealing is performed by coating an iron-nickel core wire with a copper layer of 20 to 25% by mass and further covering a surface of the copper layer with a nickel layer of 0.1 to 1.0 μm. Lead wires are also known (see, for example, Patent Document 2).
[0006]
[Patent Document 1] Japanese Patent Laid-Open No. 2003-151696 (page 4)
[0007]
[Patent Document 1] Japanese Patent Laid-Open No. 9-245748 (page 4)
[0008]
[Problems to be solved by the invention]
As in the above prior art, the sealing lead wire using nickel wire as the external lead wire has good appearance because the external lead wire has good corrosion resistance, but the external lead wire is too soft, so the external lead wire is constant. It is difficult to temporarily hold this shape, and there is a problem that it is difficult to process during wiring work.
[0009]
On the other hand, a sealing lead wire using an external lead wire obtained by coating an iron-nickel core wire with 20 to 25% by mass of copper under a hydrogen reduction atmosphere is known. Since the external lead wire of this sealing lead wire has a certain degree of rigidity, it can be temporarily held in the bent shape at the time of wiring work, so that it is easy to process and is often used in practice.
[0010]
However, since the surface layer of this external lead wire is copper, it is easily discolored and there is a problem in appearance. Although it is possible to improve the corrosion resistance by subjecting the surface of the copper layer to a special plating process, it is not practical because the cost increases.
[0011]
The present invention has been made in view of the above problems, and is a sealing lead wire having an external lead wire that can be connected to a sealing material for hard glass, has excellent corrosion resistance and workability, and does not incur a high cost. An object of the present invention is to provide a cold cathode fluorescent lamp having this lead wire.
[0012]
[Means for achieving the object]
The sealing lead wire according to claim 1 includes a sealing material made of kovar, tungsten or molybdenum; a copper layer is coated on the surface of the iron-nickel core wire, and a nickel layer is coated on the surface of the copper layer; And an external lead wire connected to the outer end of the dressing.
[0013]
Kovar is a sealing metal which is an alloy made of iron (Fe), nickel (Ni), and cobalt (Co) and is also referred to as “Kov”, and its composition is nickel 28 to 30% by mass, cobalt 15 to 15%. 18% by mass, the balance being iron.
[0014]
This Kovar, tungsten (W) or molybdenum (Mo) is known to be used as a sealing material (sealing wire) for hard glass bulbs, but has good connection to the outer end. An external lead wire that is excellent in corrosion resistance and workability and does not cause an increase in cost has not been known.
[0015]
Therefore, the inventor tried to connect various materials to the hard glass bulb sealing portion and tested, and the lead wire coated with the copper layer and the nickel layer on the iron-nickel core wire was connected to the outer end portion. We found no problems and excellent corrosion resistance and workability. In particular, since this lead wire is frequently used as a sealing member for soft glass bulbs, the cost can be relatively low. Compared to lead wire materials that have undergone special plating to ensure corrosion resistance. This makes it possible to reduce costs.
[0016]
The cold cathode fluorescent lamp according to claim 2 is a bulb made of hard glass having a phosphor layer formed on an inner surface thereof; a discharge medium enclosed in the bulb; and hermetically sealed at both ends of the bulb. A lead wire for sealing according to claim 1; and a cold cathode connected to each inner end portion of the lead wire.
[0017]
The invention of claim 2 can provide a cold cathode fluorescent lamp comprising the lead wire for sealing of claim 1.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional view showing the cold cathode fluorescent lamp of the present embodiment, and FIG. 2 is an enlarged sectional view showing external lead wires of the cold cathode fluorescent lamp of FIG.
[0019]
L is a cold cathode fluorescent lamp. For example, the power consumption of a straight tube type is 5 W or less, for example, 2.5 W. This lamp L includes a tubular bulb 1 made of hard glass made of borosilicate glass (thermal expansion coefficient: about 4 × 10 ⁻⁶ ) having an outer diameter of 2.6 mm, an inner diameter of about 1.6 mm, and a length of about 200 mm. Have. Both ends of the tubular bulb 1 are sealed with bead glass 2 welded to the sealing material 4 of the sealing lead wire 3.
[0020]
On the inner wall surface of the bulb 1, a three-wavelength phosphor layer P in which phosphors having light emitting regions in blue, green, and red are mixed is formed. The bulb 1 is filled with mercury with a mixed gas of neon (Ne) and argon (Ar) of about 8000 Pa.
[0021]
The sealing material 4 used for the lead wires 3 and 3 for sealing is a Kov wire (composition of Kovar Fe of about 53 mass%, Ni of about 28 mass%, Co of about 18 mass%), and a wire diameter of about 0.6 mm. A wire material having a length of about 4 mm. An external lead wire 5 is welded to the outer end portion of the sealing material 4. The external lead wire 5 is a lead wire having a wire diameter of 0.4 mm, in which a Ni-Fe core wire 5a of 42% by mass is coated with a Cu layer 5b of 23% by mass of about 22 μm and then a Ni layer 5c of about 2 μm. The electrode 6 is a tungsten (W) or nickel (Ni) sleeve, and is connected to the inner end of the sealing material 4.
[0022]
The sealing material 4 may be made of tungsten (W) or molybdenum (Mo). In the case of tungsten (W), the sealing material 4 and the tungsten electrode 6 are integrally formed. It may be formed.
[0023]
The fluorescent lamp L is used by being incorporated as a light source of a backlight device. The backlight device is used as a predetermined display device as a liquid crystal display device such as a personal computer or a television, and a highly efficient lighting effect is obtained.
[0024]
Next, the effect of this embodiment is demonstrated. The bulb 1 of the lamp L is made of hard glass, and Kovar (Kov), tungsten (W) or molybdenum (Mo) is used as the sealing material 4. When the above-mentioned external lead wire 5 formed by coating the copper layer 5b and the nickel layer 5c on the iron-nickel core wire 5a is tested for problems in combination with the sealing material 4 for hard glass. It was confirmed that the weld connection was good and had no problems, and that the corrosion resistance and workability were excellent.
[0025]
In particular, since the external lead wire 5 is frequently used as a sealing member for a soft glass bulb, the cost can be relatively low. Therefore, a lead wire subjected to a special plating process to ensure corrosion resistance. Costs can be reduced compared to materials.
[0026]
In addition, this invention is not limited to the said embodiment. For example, the bead glass 2 as a sealing portion is not necessarily required, and the sealing material 4 may be sealed as it is at the end of the glass bulb. Further, the lamp L is not limited to a cold cathode fluorescent lamp, and the discharge maintaining medium may be other types of small tubes such as a lamp that emits a light emitting material other than mercury or a rare gas light emitting lamp that encloses xenon gas or the like. Applicable to discharge lamps. The shape of the valve is not limited to a straight tube shape, and may be bent into a U shape, a W shape, an annular shape, or the like.
[0027]
【The invention's effect】
Since the lead wire for sealing of the present invention uses a lead wire in which an iron-nickel core wire is coated with a copper layer and a nickel layer as an external lead wire connected to an outer end portion of a sealing material made of Kovar, tungsten or molybdenum. There is no problem in welding connection, and the corrosion resistance and workability are excellent, and the cost can be suppressed.
[Brief description of the drawings]
FIG. 1 is a partially cutaway front view showing an embodiment of a cold cathode fluorescent lamp of the present invention.
2 is a front cross-sectional view showing an external lead wire used in the lamp of FIG. 1. FIG.
[Explanation of symbols]
L ... lamp, 1 ... glass bulb, 2 ... glass bead as sealing part, 3 ... sealing lead wire, 4 ... sealing material, 5 ... external lead wire, 6 ... electrode.

Claims (2)

A sealing material made of Kovar, tungsten or molybdenum;
A copper layer is coated on the surface of the iron-nickel core wire, a nickel layer is coated on the surface of the copper layer, and an external lead wire connected to the outer end of the sealing material;
The lead wire for sealing characterized by comprising. A hard glass bulb with a phosphor layer formed on the inside;
A discharge medium enclosed within the bulb;
The sealing lead wire according to claim 1, which is hermetically sealed at both ends of the bulb;
A cold cathode connected to each inner end of the lead;
A cold cathode fluorescent lamp comprising:

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