WO2010119780A1

WO2010119780A1 - Lead wire

Info

Publication number: WO2010119780A1
Application number: PCT/JP2010/056050
Authority: WO
Inventors: 亮丹治; 太一郎西川; 由弘中井; 和郎山▲崎▼
Original assignee: 住友電気工業株式会社; 住電ファインコンダクタ株式会社
Priority date: 2009-04-13
Filing date: 2010-04-02
Publication date: 2010-10-21
Also published as: CN102089850A; JP2010251029A; TW201101366A; CN102089850B; KR101154269B1; JP4612727B2; KR20110079746A

Abstract

Disclosed is a lead wire for supplying electric power to an electrode part of a cold cathode fluorescent lamp, which is configured from a nickel alloy that contains not less than 0.0001% by mass but not more than 0.03% by mass of C, and not less than 1.0% by mass but not more than 9.0% by mass in total of one or more elements selected from among Mn, Si and Cr, with the balance made up of Ni and unavoidable impurities. By controlling the C content and containing the specific elements in the specific amounts, the strength of the wire itself, the strength of a welded portion and the solder wettability can be improved, while having excellent electrical conductivity and thermal conductivity. Also disclosed are a lead wire member comprising the lead wire, an electrode member, a cold cathode fluorescent lamp, and a wire suitable for the lead wire.

Description

Lead

The present invention relates to a lead wire used as a power supply line to an electrode portion of a cold cathode fluorescent lamp, a lead wire member having the lead wire, an electrode member, a cold cathode fluorescent lamp, and a wire suitable for the lead wire. Is. In particular, the present invention relates to a lead wire having high strength and excellent welding strength, oxidation resistance, and electrical conductivity.

Cold cathode fluorescent lamps are used as various light sources such as a light source for irradiating an original of an image scanner, a liquid crystal display of a personal computer, and a backlight of a liquid crystal display device (liquid crystal display) such as a liquid crystal television. As shown in FIG. 1, the cold cathode fluorescent lamp 10 typically has a phosphor layer 11 on its inner wall surface, and is disposed in the glass tube 12 with a rare gas and mercury sealed therein. A pair of electrode portions 13 and a lead portion 14 that is joined to the electrode portion 13 and supplies power to the electrode portion 13. There is also a mercury-free cold cathode fluorescent lamp in which only a rare gas is enclosed in a glass tube 12.

The lead portion 14 includes an inner lead wire 14i to which the electrode portion 13 is joined at one end, and an outer lead wire 14o that is joined to the other end of the inner lead wire 14i and mainly disposed outside the glass tube 12. Since the inner lead wire 14i seals the end of the glass tube 12 and the glass portion 15 for fixing the electrode portion 13 in the glass tube 12 is welded, the constituent material includes the thermal expansion coefficient of the glass. A material adjusted to a similar thermal expansion coefficient, for example, Kovar (KOV) is used. For the outer lead wire 14o, for example, a wire rod having a copper coating (about 20% by mass of the core material) on the outer periphery of a core material made of a 58% Ni-42% Fe alloy (see Patent Documents 1 and 2), representative In particular, the Jumet line is used. Solder 20 is applied to the outer periphery of the outer lead wire 14o, and a terminal (not shown) is connected, and electric power is supplied to the electrode portion 13 through the terminal and the lead portion 14.

In recent years, it has been desired to increase the size of liquid crystal displays and reduce power consumption. To meet this demand, the cold cathode fluorescent lamp has a longer glass tube or a cold cathode mounted on a single liquid crystal display. In order to reduce the number of fluorescent lamps, it has been studied to increase the diameter of glass tubes and electrode portions. Due to the increase in length and diameter, the weight of the cold cathode fluorescent lamp tends to increase. Such an increase in weight increases the load and vibration applied to the lead portion, particularly the outer lead wire, and therefore the outer lead wire is desired to have high strength. In particular, the strength of the outer lead wire tends to decrease by receiving heat when welding to the inner lead wire, heat when welding the glass portion to the inner lead wire, heat when sealing the glass tube, etc. It is in. Therefore, even when such a thermal history is received, development of an outer lead wire having high strength is desired.

Furthermore, due to the increase in weight, the load and vibration applied to the lead portion increase, and if the strength (welding strength) of the welded portion between the outer lead wire and the inner lead wire is low, the welded portion is damaged, There is a risk that both will come off. Therefore, considering the increase in length and diameter, it is desired to improve the welding strength of the lead portion as compared with the conventional case.

In addition, the increase in the weight increases the load and vibration applied to the lead part. If the wettability of the outer lead wire with the solder is low, the lead part and the terminal may come off. Therefore, considering the increase in length and diameter, it is desired to improve the wettability of the outer lead wire with the solder compared to the conventional case.

Furthermore, the cost can be reduced by reducing the number of cold cathode fluorescent lamps mounted on a liquid crystal display or the like. However, by reducing the number of wires, the current flowing per cold cathode fluorescent lamp is increased in order to maintain a predetermined brightness, so the lead wires have electrical and thermal conductivity that can withstand large currents. It is desirable to have

Therefore, a main object of the present invention is to provide a lead wire having high strength, high welding strength, excellent wettability with solder, and high electrical conductivity and thermal conductivity. Another object of the present invention is to provide a lead wire member having the lead wire, an electrode member having the lead wire member, a cold cathode fluorescent lamp having the electrode member, and a wire suitable for the lead wire. It is to provide.

The present inventors examined various compositions in developing a lead wire having high strength, high strength at the welded portion, and excellent wettability with solder. As a result, it was found that a high-strength wire can be obtained by using nickel (Ni) as a base material and adding a specific element in a specific range. And the nickel alloy containing the said specific element acquired knowledge that it became difficult to form an oxide film by being excellent in oxidation resistance, and wettability with a solder improved as a result of few oxide films. In addition, the nickel alloy containing the specific element described above is excellent in electrical conductivity because the electrical resistivity of the material does not become excessive, and even when a large current is passed, the lead wire does not generate much heat, and the cooling caused by the heat generation is low. The knowledge that the malfunction of the electrode part vicinity of a cathode fluorescent lamp can be suppressed was acquired. In addition, by controlling the carbon (C) within a specific range, the surface tension of the lead wire is reduced during welding, resulting in improved wettability. As a result, the inner lead wire can be firmly welded and welded. The knowledge that the strength can be improved was obtained. The present invention is based on these findings.

The lead wire of the present invention is a wire for supplying power to the electrode portion of the cold cathode fluorescent lamp, and C is at least one selected from 0.0001 mass% to 0.03 mass%, Mn, Si, and Cr. The total amount of elements is 1.0% by mass or more and 9.0% by mass or less, and the balance is made of a nickel alloy composed of Ni and inevitable impurities. Further, the wire of the present invention contains C in an amount of 0.0001 mass% to 0.03 mass%, and contains at least one element selected from Mn, Si, and Cr in a total of 1.0 mass% to 9.0 mass%, with the balance being It is made of a nickel alloy composed of Ni and unavoidable impurities, and can be suitably used as a material for the lead wire of the present invention.

The lead wire of the present invention having the above-described configuration and the wire of the present invention can be made of a nickel alloy containing a specific element in a specific range, thereby having high strength due to solid solution strengthening of the element. Therefore, even if the lead wire of the present invention or the lead wire made of the present wire is softened by heat at the time of welding or heat at the time of glass welding, it can maintain high strength. In addition, the lead wire of the present invention and the wire of the present invention are composed of a nickel alloy mainly containing nickel and containing a specific element, and are excellent in oxidation resistance. Excellent wettability. Furthermore, the lead wire of the present invention and the wire of the present invention contain a relatively small amount of C, so that during welding, the dissolved oxygen in the molten pool is increased to reduce the surface tension of the lead wire and improve the wettability. Can be welded firmly. Therefore, the welded portion of the lead wire of the present invention or the lead wire made of the wire of the present invention and the inner lead wire has high strength. In addition, the lead wire of the present invention or the lead wire of the present invention can be suitably used as a power supply line because (1) it has excellent electrical conductivity by using nickel as the main constituent material. (2) Because of its excellent thermal conductivity, it is possible to reduce the heat generation near the electrode even when a large current flows, and the brightness of the cold cathode fluorescent lamp decreases with increasing temperature and the electrode There is an effect that heat deterioration of peripheral elements can be prevented. The lead wire of the present invention is excellent in various characteristics such as mechanical characteristics, wettability with solder, wettability during welding, and electrical characteristics as described above, and the minimum level of these characteristics is high. By using such a lead wire of the present invention or a wire of the present invention, it is possible to stably manufacture a cold cathode fluorescent lamp having sufficient characteristics and its components even if there are some variations in characteristics. it can. Therefore, even when automating the manufacturing process (welding, glass welding, soldering, etc.) to improve the productivity of the cold cathode fluorescent lamp and its components, it is possible to manufacture a highly reliable product. It is expected.

The lead wire of the present invention has high strength and high electrical conductivity, excellent wettability with solder, and high strength of the welded portion.

FIG. 1 is a cross-sectional view showing a schematic configuration of a cold cathode fluorescent lamp.

Hereinafter, the present invention will be described in more detail. In addition, the dimension ratio of drawing does not necessarily correspond with the thing of description.
[Lead wire, wire]
(composition)
One of the characteristics of the lead wire of the present invention and the nickel alloy constituting the wire of the present invention is that the content of C (carbon) is relatively small, and C: 0.0001 mass% or more and 0.03 mass% or less. Commercially available pure Ni (99% by mass or more is Ni) often contains 0.10% by mass or more of C. Therefore, if commercially available pure Ni is used as a raw material as it is, the content of C exceeds 0.03% by mass. Can be a nickel alloy. When the content of C in the nickel alloy is more than 0.03% by mass, the strength is improved by increasing C, but the wettability during welding is low and the strength of the welded portion is low. The reason why the wettability is low is that when the content of C is increased, carbon-containing gas such as CO (carbon monoxide) and carbon dioxide gas is easily generated during welding and combined with dissolved oxygen in the weld pool. This is probably because the surface tension of the lead wire is increased by reducing the amount of dissolved oxygen due to gas generation. Further, the vicinity of the joint portion of the outer lead wire with the inner lead wire may be covered with glass during glass welding. If the carbon-containing gas is generated during glass welding or the like, bubbles of the gas may be formed inside the end portion of the glass portion (near the lead portion) in the cold cathode fluorescent lamp. The bubbles are the starting points of cracks at the end of the sealed glass part, and the cracks propagate, so that gases such as rare gases enclosed in the glass tube leak to the outside of the glass tube through the cracks. This can cause the life of the cold cathode fluorescent lamp to be shortened. Therefore, in the present invention, the upper limit of the C content is 0.03% by mass. On the other hand, if the content of C is too small, oxygen in the atmosphere is taken into the nickel alloy during welding, and oxides such as oxygen and additive elements in the nickel alloy are precipitated, thereby increasing the strength of the welded part. It is thought to decrease. Therefore, in the present invention, the lower limit of the C content is 0.0001% by mass. A more preferable content of C is 0.005% by mass or more and 0.01% by mass or less. In order to bring the C content into the above range, a material having a low C content may be used as a raw material, or adjustment (reduction) may be performed by refining.

The nickel alloy constituting the lead wire of the present invention and the wire of the present invention contains, as an additive element, one or more elements selected from Mn, Si, and Cr in total of 1.0 mass% or more and 9.0 mass% or less. One of the features. A more preferable total content is 2.0% by mass or more and 5.0% by mass or less. The content of the additive element can be adjusted to the above range by adjusting the amount of the element added as a raw material.

By containing Mn, (1) oxidation resistance and strength can be improved. (2) When using a burner for glass welding, etc., it is possible to reduce material embrittlement due to sulfur in the combustion gas. It has the effect of being able to. A preferable content of Mn is 0.01% by mass or more and 4.0% by mass or less. If it is less than 0.01% by mass, it is difficult to sufficiently improve the strength and oxidation resistance, and if it exceeds 4.0% by mass, the electrical conductivity and thermal conductivity are likely to be lowered.

Strength can be improved by containing Si and Cr. In particular, when one or more elements of Si and Cr are contained, the oxidation resistance tends to be superior as compared with the case of containing only Mn. Therefore, it is preferable to contain at least one element of Si and Cr, or at least one element of Si and Cr, and Mn, and more preferably to contain all three elements. A preferable total content of one or more elements of Si and Cr is 0.01% by mass or more and 6.0% by mass or less. If it is less than 0.01% by mass, it is difficult to sufficiently improve the strength and oxidation resistance, and if it exceeds 6.0% by mass, the electrical conductivity and thermal conductivity are likely to be lowered.

Furthermore, as an additive element, at least one element selected from Mg, Al, and Ti can be contained in a total amount of 0.001% by mass to 2.0% by mass. These elements function as enhancing elements for the effects of Mn, Si, and Cr. Specifically, by containing Mg, Al, Ti, the oxidation of Mn, Si, Cr is suppressed at the time of melting, and the strength improvement effect, oxidation resistance improvement effect, etc. by containing Mn, Si, Cr, etc. It can be fully demonstrated. Further, by containing Mg, Al, and Ti, the workability of the nickel alloy (plastic workability such as rolling and wire drawing) can be improved, and the lead wire manufacturability is excellent. When the content is less than 0.001% by mass, the above-described effects are hardly obtained. When the content is more than 2.0% by mass, the electrical conductivity and the thermal conductivity are easily lowered. A more preferable total content is 0.003% by mass or more and 1.5% by mass or less.

The lead wire of the present invention and the nickel alloy constituting the wire of the present invention contain the above-mentioned additive elements, and the balance is made of Ni and inevitable impurities. When the Ni content is 90% by mass or more, it is excellent in oxidation resistance as described above, and it is difficult to form an oxide film, so that soldering is easy and heat conductivity is also excellent.

[Mechanical properties]
The lead wire of the present invention and the wire of the present invention have high strength as described above, and specifically, the tensile strength satisfies 450 MPa or more. In addition, the lead wire of the present invention and the wire of the present invention are excellent in toughness while having high strength, and specifically, the elongation is 20% or more. Although it depends on the composition, wire drawing conditions, heat treatment conditions, etc., as one embodiment of the lead wire of the present invention and the wire of the present invention, a wire material satisfying a tensile strength of 500 MPa or more and an elongation of 40% or more can be obtained.

[Oxidation resistance]
The lead wire of the present invention and the wire of the present invention are excellent in oxidation resistance as described above. Specifically, after heating the lead wire or wire having the above specific composition in the atmosphere at 900 ° C. for 72 hours, the thickness of the oxide film formed on the surface of the lead wire or wire after heating is 100 μm or less. It is. The condition of "900 ° C x 72 hours" is a very severe condition because the temperature is higher than the heat condition given to the lead wire by the heat at the time of welding and the heat at the time of glass welding, and the heating time is long. It is. It can be evaluated that the oxidation resistance is excellent if the thickness of the oxide film is thin even if heating under such severe conditions is performed. Therefore, in the present invention, the condition “900 ° C. × 72 hours in air” is adopted as an index for evaluating oxidation resistance. As described above, when containing at least one element of Si and Cr as an additive element, it is superior in oxidation resistance. Therefore, as one embodiment of the lead wire of the present invention, oxidation after heating at 900 ° C. for 72 hours in the atmosphere. A wire having a thickness of 60 μm or less can be obtained. In addition, it is good to measure an oxide film with respect to the wire with which solder etc. adhered, after removing solder and heating on the above-mentioned conditions.

[Electric conductivity and thermal conductivity]
The lead wire of the present invention and the wire of the present invention are also excellent in electrical conductivity and thermal conductivity as described above. Although it depends on the composition and the like, the lead wire of the present invention or the wire of the present invention can be a wire satisfying a specific resistance of 0.2 μΩm or less and a thermal conductivity of 45 W / m · K or more.

[Production method]
The lead wire of the present invention and the wire of the present invention are obtained, for example, by melting → casting → hot rolling → cold drawing and heat treatment. More specifically, a nickel alloy melt with adjusted components is prepared in a vacuum, and the melt is refined to adjust the C content, to remove or reduce impurities and inclusions, and to control the temperature. To make adjustments. Casting such as vacuum casting is performed on the molten metal to obtain an ingot. The ingot is hot-rolled to obtain a rolled wire. Cold rolling and heat treatment are repeatedly performed on the rolled wire to obtain the lead wire of the present invention and the wire of the present invention. A final heat treatment (softening treatment) may be performed, and in that case, it is preferably performed at about 700 to 1000 ° C., particularly about 800 to 900 ° C. in a hydrogen atmosphere or a nitrogen atmosphere. Further, when a long lead wire of the present invention is prepared and the lead wire of the present invention is manufactured by appropriately cutting to a predetermined length, the productivity is excellent.

[Lead wire material]
The lead wire member of the present invention includes the above-described lead wire of the present invention and an inner lead wire joined to one end of the lead wire by welding. As described above, the lead wire of the present invention has excellent wettability by reducing the surface tension during welding, and thus is firmly joined to the inner lead wire. Therefore, the lead wire member of the present invention has high welding strength. Examples of the inner lead wire include a wire made of an Fe—Ni—Co alloy such as Kovar, a jumet wire, and a wire made of Mo or W.

[Electrode member]
The electrode member of the present invention comprises the lead wire member of the present invention having the lead wire of the present invention, a glass portion bonded to the outer periphery of the inner lead wire, and an electrode portion bonded to the other end of the inner lead wire. Have. As described above, the lead wire member of the present invention has high strength at the welded portion between the lead wire of the present invention and the inner lead wire, and the lead wire of the present invention has a low C content. A carbon-containing gas is unlikely to be generated by heating such as when forming a glass part by welding beads. Therefore, this electrode member has high welding strength, and there are substantially no bubbles in the glass portion. Examples of the glass part and the glass tube described below include those made of hard glass such as borosilicate glass and aluminosilicate glass, and soft glass such as soda lime glass. The electrode portion is made of nickel alloy, Fe, Fe alloy, W, Mo or the like described in Patent Documents 1 and 2 in addition to pure Ni, and includes a bottomed cylindrical cup shape and a columnar shape.

[Cold cathode fluorescent lamp]
The cold cathode fluorescent lamp of the present invention includes a glass tube filled with an enclosed gas, a phosphor layer formed on the inner wall of the glass tube, and the electrode member. An electrode portion of the electrode member is inserted into an end portion in the glass tube, and the electrode portion is fixed to the glass tube through the glass portion. The cold cathode fluorescent lamp of the present invention includes the lead wire of the present invention having high welding strength, excellent wettability with solder, and high strength as described above. Therefore, in the cold cathode fluorescent lamp of the present invention, even if the glass tube or the electrode portion has a large diameter, or the glass tube is long, the lead wire is disconnected or the welded portion or the solder portion is disconnected. It is difficult to use for a long time. In addition, by providing the lead wire of the present invention excellent in electrical conductivity and thermal conductivity, the cold cathode fluorescent lamp of the present invention is less prone to problems due to heat generation of the lead wire even when a large current flows. From this, it is expected that it can be used for a long time. Examples of the phosphor layer include those made of a halophosphate phosphor. Examples of the sealing gas include a rare gas and mercury, or mercury. At least one electrode part is disposed in the glass tube, and the glass part and the end part of the glass tube are melted to form a sealed state. Typically, a form in which electrode portions are arranged on both end sides in a cylindrical glass tube, that is, a form having a pair of electrode portions, can be mentioned.

Hereinafter, embodiments of the present invention will be further described.
Assuming an outer lead wire used for a cold cathode fluorescent lamp, a plurality of wires made of nickel alloy were produced, and the characteristics of each wire were evaluated.

Sample Nos. 1 to 11 were prepared as follows. Using a normal vacuum melting furnace, a molten nickel alloy having the composition shown in Table 1 (unit: mass%) was prepared, and the molten metal temperature was adjusted as appropriate to obtain an ingot by vacuum casting. Commercially available pure Ni (99.0 mass% or more Ni) and grains of each additive element were used as the raw material for the molten metal. The molten metal was refined to reduce and remove impurities, and the C content was changed by adjusting the degree of refinement. The obtained ingot was hot-rolled to obtain a rolled wire having a wire diameter of 5.5 mmφ. The rolled wire was subjected to a combination of cold drawing and heat treatment, and the resulting wire was subjected to final heat treatment (softening treatment: temperature: 800 ° C., nitrogen atmosphere) to obtain a soft material having a wire diameter of 0.6 mmφ. Samples Nos. 1 to 11 were obtained by cutting each soft material to an appropriate length. The composition of each obtained sample was examined using an ICP emission spectroscopic analyzer, and it was the same as the composition shown in Table 1, with the balance being Ni and inevitable impurities. Samples Nos. 1 to 11 all have 90% by mass or more of Ni. The composition can be analyzed by the atomic absorption spectrophotometry method as well as the above ICP emission spectroscopic analysis method. Moreover, the carbon content of each obtained sample was measured by the high frequency combustion infrared absorption method. The results are shown in Table 1.

Sample No. 100 is a commercially available Mn-Ni alloy wire, and sample No. 102 is a commercially available jumet wire (Cu coating: 22.5% by mass with the core material of the composition shown in Table 1 + Cu coating as 100%). Sample No. 101 is a sample that has few additive elements and has not been refined to reduce the C content. Sample No. 103 is a sample manufactured in the same manner as Sample Nos. 1 to 11 with many additional elements. Sample Nos. 100 to 103 all have a wire diameter of 0.6 mmφ.

The oxidation resistance of each of the above samples was evaluated. The results are shown in Table 2. For oxidation resistance, each sample was heated in the atmosphere at 900 ° C for 72 hours, then a longitudinal section was taken, and the thickness of the oxide film formed on the surface of the sample was measured from this cross-sectional photograph (sample No. 102 is The thickness of the oxide film formed on the surface of the Cu coating was measured), and the thickness of the oxide film was evaluated. It can be said that the thinner the oxide film, the better the oxidation resistance. Here, in the cross-sectional photograph of each sample, the thicknesses of five arbitrary points were measured, and the average was taken as the thickness of the oxide film of the sample.

The mechanical properties of each sample were evaluated. The results are shown in Table 2. Mechanical properties were evaluated by performing a tensile test according to the provisions of JIS Z 2241 and measuring tensile strength and elongation.

For each sample, the strength (fatigue strength) of the welded portion was evaluated. The results are shown in Table 2. The strength of the welded part was evaluated by the number of repetitions by performing a rotating bending fatigue test (JIS Z 2274) with a stress amplitude of 200 MPa. Specifically, one end face of a commercially available Kovar (Fe—Ni—Co alloy) wire having a wire diameter of 0.6 mmφ was joined to one end face of each sample by resistance welding to produce a lead wire member. Then, both ends of the lead wire member (the other end side of the joined sample and the other end side of the Kovar wire) are sandwiched with a chuck, and a rotating bending test is performed so that a welded portion is arranged at the center of the chucked portion, The number of repetitions until the welded portion was broken (broken) was measured.

Each of the above samples was evaluated for electrical conductivity and thermal conductivity. The results are shown in Table 2. The electrical conductivity was evaluated by measuring the specific resistance by the four probe method, and the thermal conductivity was evaluated by measuring the thermal conductivity with a commercially available laser flash device.

For each of the above samples, a glass sealing test was performed to examine the foaming state of the glass. The results are shown in Table 2. In this test, lead wires were prepared by welding each sample and a commercially available Kovar wire as described above, and these lead wires were oxidized to form a slight oxide film on the surface. -Glass beads were welded so that the glass was welded to a part of each sample, and then the foamed state of the glass was visually observed. When glass has foam: x, when no foam: o

As shown in Table 2, Sample Nos. 1 to 11 containing one or more of Mn, Si, and Cr in a specific range and C in a specific range have a tensile strength of 450 MPa or more and an elongation of It is 20% or more (many is 40% or more), and it can be seen that it is excellent in toughness while having high strength. Compared with sample Nos. 100, 101, and 103 in which at least one of the contents of Mn, Si, Cr and C is out of a specific range, sample Nos. 1 to 11 have a good balance between strength and toughness. You can see that Samples Nos. 1 to 11 are soft materials that have undergone the final softening treatment, yet have high strength, so they are sufficiently high even when subjected to heat history due to heat during welding or heat during glass welding. Expected to maintain strength.

Also, it can be seen that Sample Nos. 1 to 11 have higher fatigue strength at the welded portion than Sample Nos. 100 and 101 and Sample No. 102 which is a dumet wire rod. Samples Nos. 1 to 11 are excellent in oxidation resistance, and even after being heated in the atmosphere at 900 ° C. for 72 hours, the thickness of the oxide film is 100 μm or less (mostly 60 μm or less). . Samples Nos. 1 to 11 having excellent oxidation resistance are expected to have high wettability with solder. Furthermore, sample Nos. 1 to 11 are more electrically conductive and thermally conductive than sample No. 102, which is a jumet wire, and sample No. 103, which contains more Mn, Si, Cr than the specified range. It is understood that it is excellent. In addition, it can be seen that Sample Nos. 1 to 11 having a relatively low C content are less likely to generate bubbles inside the glass even when the glass is deposited. On the other hand, it can be seen that Samples Nos. 100 and 101 with a high C content may cause bubbles in the glass. From this, it is considered that when the content of C is large, a carbon-containing gas is easily generated and bubbles are easily generated.

As described above, a wire containing one or more of Mn, Si, and Cr in a specific range and having C in a specific range has high strength and excellent weld strength and wettability with solder. The structure of a cold cathode fluorescent lamp, such as a lead wire of a cold cathode fluorescent lamp, a lead wire member including the lead wire, and an electrode member including the lead wire member, is excellent in electrical conductivity and thermal conductivity. It is expected that it can be suitably used for parts. In particular, the lead wire made of the wire having the above specific composition is used as a component of a long cold cathode fluorescent lamp having a glass tube of 1300 mm or more, or a cold cathode fluorescent lamp having a large diameter of glass tube of 4.0 mmφ or more. It is expected that it can be used sufficiently. In addition, the cold cathode fluorescent lamp having a lead wire composed of the wire having the above specific composition is less likely to cause a malfunction due to breakage of the lead wire or destruction of the welded portion, gas leakage inside the glass tube due to the presence of bubbles, heat generation, Expected to have a long life.

It should be noted that the above-described embodiment can be modified as appropriate without departing from the gist of the present invention, and is not limited to the above-described configuration. For example, the composition and size (diameter) of the lead wire can be appropriately changed.

The lead wire, lead wire member, and electrode member of the present invention can be suitably used for components of a cold cathode fluorescent lamp. The wire of the present invention can be suitably used as a material for the lead wire. The fluorescent lamp of the present invention is a light source for various electrical devices such as a backlight light source for a liquid crystal display, a front light source for a small display, a light source for illuminating a document such as a copying machine or a scanner, or an eraser light source for a copying machine. Can be suitably used.

10 Cold cathode fluorescent lamp 11 Phosphor layer 12 Glass tube 13 Electrode part 14 Lead part 14i Inner lead wire 14o Outer lead wire 15 Glass part 20 Solder

JP 2007-173197 A JP 2008-123722 A

Claims

A lead wire for supplying power to the electrode portion of the cold cathode fluorescent lamp,
Nickel containing 0.0001 mass% or more and 0.03 mass% or less of C, one or more elements selected from Mn, Si, and Cr in total of 1.0 mass% or more and 9.0 mass% or less, with the balance being Ni and inevitable impurities A lead wire comprising an alloy.
The lead wire according to claim 1, further comprising one or more elements selected from Mg, Al, and Ti in total of 0.001% by mass to 2.0% by mass.
3. The lead wire according to claim 1, wherein the lead wire has a tensile strength of 450 MPa or more and an elongation of 20% or more.
4. The lead wire is heated in the atmosphere at 900 ° C. for 72 hours, and then the thickness of the oxide film formed on the surface of the lead wire after the heating is 100 μm or less. Or the lead wire according to item 1.
The lead wire according to any one of claims 1 to 4,
A lead wire member comprising an inner lead wire joined to one end of the lead wire by welding.
The lead wire member according to claim 5,
A glass portion bonded to the outer periphery of the inner lead wire;
An electrode member comprising: an electrode portion joined to the other end of the inner lead wire.
A glass tube filled with a filling gas;
A phosphor layer formed on the inner wall of the glass tube;
Comprising the electrode member according to claim 6,
The cold cathode fluorescent lamp, wherein an electrode portion of the electrode member is inserted into an end portion of the glass tube, and the electrode portion is fixed to the glass tube through the glass portion.
Nickel containing C in a range of 0.0001 mass% to 0.03 mass%, one or more elements selected from Mn, Si, and Cr in total of 1.0 mass% to 9.0 mass% with the balance being Ni and inevitable impurities A wire comprising an alloy.