JP2008251268A - Electrode mount and cold-cathode fluorescent lamp using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode mount capable of radiating heat generated from an electrode efficiently when a lamp is lighted, and a cold-cathode fluorescent lamp of high reliability using this. <P>SOLUTION: The electrode mount 4 is to be sealed and fitted to both ends of a glass bulb via a bead glass, and equipped with the electrode 6 and a lead-in wire 7. The lead-in wire 7 is equipped with a sealing pin 9 and an outer lead wire 10 in the order from a side to be joined to the electrode 6, and the sealing pin 9 is joined so that a joint face of the sealing pin 9 and the electrode 6 have the same surface level via a low melting point bonding material 8 constituted of a metal material of which the melting point is 1,800°C or less. The sealing pin 9 is constituted of the same metal material as the electrode 6, and its melting point is 2,000°C or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrode mount sealed at both ends of a glass bulb, and a cold cathode fluorescent lamp that uses this electrode mount and is used as a backlight light source of a liquid crystal display device such as a liquid crystal television.

  The cold cathode fluorescent lamp has a structure in which a discharge medium composed of mercury and a rare gas is sealed in a glass bulb whose ends are sealed with electrode mounts via bead glass, and a phosphor film is deposited on the inner surface of the glass bulb. The structure is known.

  The electrode mount includes an electrode and an introduction line connected to the electrode, and a bead glass is attached to the introduction line, which is inserted into both ends of the glass bulb and heated to be sealed.

  However, if the lamp is lit for a long time with both ends of the glass bulb sealed with the electrode mount, the bonding strength between the electrode constituting the electrode mount and the lead-in wire will decrease, and the electrode will fall off the lead-in wire. Easy to fall into the valve.

  Accordingly, an electrode mount has been proposed in which an intermediate member made of a metal material (for example, nickel) is interposed between the electrode and the lead wire, and the electrode, the intermediate member, and the lead wire are fixed by welding (for example, Patent Document 1).

However, in such a conventional electrode mount, since an intermediate member is interposed between the electrode and the lead-in wire, it is difficult to efficiently dissipate the heat generated from the electrode when the lamp is turned on. There was a tendency to reduce performance.
JP 2002-270131 A

  An object of the present invention is to cope with such a problem. An electrode mount capable of efficiently dissipating heat generated from an electrode when the lamp is turned on and a highly reliable cold cathode fluorescent lamp using the same are provided. It is to provide.

  The electrode mount according to claim 1, wherein the electrode is made of a metal material having a melting point of 2000 ° C or higher; and the electrode mount is joined to the electrode through a low melting point bonding material made of a metal material having a melting point of 1800 ° C or lower. A sealing member made of a metal material similar to that of the electrode, the sealing member and the welded portion being joined so that at least a part thereof is in contact with the electrode via the low-melting-point bonding material And a lead wire having an external lead wire having a core wire and a coating layer covering the core wire.

  The electrode mount according to claim 2 is the electrode mount according to claim 1, wherein the welded portion includes a core wire melting portion formed by melting the core wire of the external lead wire and a coating layer melt formed by melting the coating layer. It is characterized by providing a part.

  The electrode mount according to claim 3, wherein the electrode is made of a metal material having a melting point of 2000 ° C. or higher; and the electrode mount is joined to the electrode through a low melting point bonding material made of a metal material having a melting point of 1800 ° C. or lower. A sealing member that is a wire and is joined via the low-melting-point bonding material without contacting the electrode within a range of a distance of 0.05 mm or less from the electrode, and is made of the same metal material as the electrode And an introduction wire having a core wire and a coating layer covering the core wire, which are joined to the sealing member via a welded portion.

  The cold cathode fluorescent lamp according to claim 4, wherein both ends of the glass bulb are sealed; and the electrode mount according to any one of claims 1 to 3, which is sealed at both ends of the glass bulb; And a phosphor film deposited on the inner surface of the glass bulb; and a discharge medium sealed in the glass bulb.

  In the above-described inventions according to claims 1 to 4, the definitions and technical meanings of terms are as follows unless otherwise specified.

  The electrode mount includes an electrode and a lead wire joined to the electrode via a low melting point bonding material. The electrode mount is sealed at both ends of the glass bulb via bead glass. As a sealing method, the bead glass is attached to the lead-in wire and inserted into the both ends of the glass bulb. Sealed by heating.

  The electrode is disposed in the glass bulb, and the shape thereof is a cylindrical or quadrangular prism casing. The electrode is made of a metal material having a melting point of 2000 ° C. or higher, preferably 2500 to 3500 ° C. Examples of such a metal material include molybdenum, tungsten, and tantalum, and these can be used alone or in an alloy of two or more. The electrode is bonded to the lead-in wire via a low melting point bonding material.

  The low melting point bonding material is a temperature that is difficult to melt when the lamp is turned on, and has a lower melting point than the metal material constituting the electrode and lead wire to be joined by the bonding material, that is, the melting point is 1800 ° C. or less, preferably 1000 It is composed of a metal material having a low melting point of ˜1800 ° C. Examples of such a metal material include nickel, iron, cobalt, and the like, and these can be used alone or in an alloy of two or more.

  The lead-in wire is an electrode support member that is bonded to the electrode via a low-melting point bonding material, introduces and supplies current to the electrode, and supports the electrode in the valve. The lead-in wire includes a sealing member and an external lead wire in order from the side joined to the electrode.

  Hereinafter, the sealing member constituting the lead-in wire and the external lead wire will be described.

  The sealing member is a member that seals the electrode mount to the glass bulb by attaching bead glass, and a pin-shaped member is generally used. In addition, the sealing member is bonded to the electrode via a low-melting point bonding material, and in the present invention, at least a part of the sealing member is in contact with the electrode or the sealing member Even when the electrode is not in contact with the electrode, the distance between the bottom surface of the electrode and the end surface of the sealing pin (hereinafter referred to as the separation distance) is 0.05 mm or less and is bonded via the low melting point bonding material. ing. In particular, it is preferable that the joint surface between the sealing member and the electrode be flush with each other in order to efficiently dissipate the heat generated from the electrode when the lamp is turned on. The sealing member is made of the same metal material as the electrode.

The external lead wire is a rod-like body joined to the sealing member via a welded portion, and one end of the external lead wire protrudes outside the valve. The external lead wire includes a core wire and a coating layer that covers the core wire. The core wire has a melting point of less than 2000 ° C., preferably 1300 to 1800 ° C., and is made of a metal material having a linear expansion coefficient of 14.0 × 10 ⁻⁶ / ° C. or less. Examples of such a metal material include iron, nickel, cobalt, and the like, and these can be used alone or in an alloy of two or more. On the other hand, the coating layer is made of a metal material having a melting point of less than 2000 ° C. and a linear expansion coefficient of 15.0 × 10 ⁻⁶ / ° C. or more. Examples of such a metal material include copper, manganese, aluminum, and the like, and these can be used alone or in an alloy of two or more.

  The welded portion is a weld ball formed when one end portion of the external lead wire is heated and melted and fused to the sealing member, and a core wire melted portion formed by melting the core wire of the external lead wire, and this core wire And a coating layer melting part formed by melting the coating layer. Thus, in the present invention, in the welded portion, the melted core wire and the coating layer are not alloyed with each other, and the core wire melting portion and the coating layer melting portion are provided independently of each other.

  The configuration of the cold cathode fluorescent lamp of the present invention to which the above electrode mount is applied will be described below. The cold cathode fluorescent lamp of the present invention includes a glass bulb, an electrode mount, a phosphor film, and a discharge medium.

  The glass bulb is an airtight container whose both ends are hermetically sealed with electrode mounts. Further, the shape of the glass bulb may be a straight tube, an annular shape, a U-shape, a W-shape, a double or triple U-shape, or a combination of a plurality of straight-tube glass bulbs. As the material of the glass bulb, soft glass (such as soda glass or lead glass) or hard glass (such as borosilicate glass, aluminosilicate glass, or quartz glass) can be used. The glass bulb preferably has a lamp length (discharge path length) of 40 to 2000 mm, an inner diameter of 1.2 to 9.0 mm, and an outer diameter of 1.6 to 10.0 mm.

  As described above, the electrode mount includes an electrode and a lead-in wire, and bead glass is attached to the lead-in wire, which is inserted into both ends of the glass bulb and heated to be sealed at both ends of the bulb.

The phosphor film is deposited and formed on the inner surface of the glass bulb. The thickness of the phosphor film is preferably 20 to 40 μm. The phosphor film is formed by applying phosphor slurry on the inner surface of the bulb, followed by drying and firing in this order. The phosphor slurry is composed of a phosphor, a binder (for example, alumina), a dispersant (for example, a carboxylic acid type dispersant), a thickener (for example, nitrocellulose or polyethylene oxide), and a solvent (for example, butyl acetate or water). ) And are sufficiently stirred. The phosphor has three wavelengths consisting of three types of phosphors: a red phosphor (Y ₂ O ₃ : Eu), a green phosphor (LaPO ₄ : Ce, Tb), and a blue phosphor (BaMgAl ₁₀ O ₁₇ : Eu). A light emitting phosphor (hereinafter referred to as a three-wavelength phosphor), a continuous wavelength light emitting halophosphate phosphor, or the like can be used. The phosphor is appropriately selected and used depending on the type and application of the lamp. It should be noted that a protective film made of a metal oxide (for example, aluminum oxide, yttrium oxide, zinc oxide, etc.) is used as a base between the phosphor film and the glass bulb as needed, as long as the effects of the present invention are not impaired. Alternatively, a transparent conductive film may be formed.

  The discharge medium is enclosed in a glass bulb and is composed of a rare gas or a rare gas and mercury. The rare gas is at least one selected from argon (Ar), neon (Ne), krypton (Kr), and xenon (Xe). The mixing ratio and the sealing pressure can be appropriately adjusted according to the lamp characteristics, but the sealing pressure is preferably in the range of 40 to 120 Torr. Mercury may be liquid mercury. For example, an amalgam composed of at least one metal selected from zinc (Zn), lead (Pb), tin (Sn), bismuth (Bi) and indium (In) and mercury is used. It can be encapsulated in the form of a granular shape, or a GEMEDIS (trade name) obtained by processing a mercury alloy into a plate shape. The amount of mercury enclosed may be in a range that does not adversely affect the environment and can ensure the lighting stability of the lamp.

  According to the electrode mount of claim 1, by joining the electrode and the sealing member so that at least a part thereof is in contact, heat generated from the electrode can be efficiently radiated when the lamp is turned on. Damage and performance degradation due to temperature rise can be suppressed.

  According to the electrode mount of the second aspect, the Cu component of the molten coating layer comes into contact with the sealing member by preventing the molten core wire and the coating layer from alloying with each other in the welded portion of the lead-in wire. Since it can be made difficult, it is possible to reduce cracks on the surface and the inside of the welded portion, starting from the location where the molten Cu component is in contact with the sealing member, and improving the joint strength of the welded portion. Can be planned.

  According to the electrode mount of claim 3, even if the sealing member and the electrode are not in contact with each other, the separation distance between the electrode and the sealing member is within 0.05 mm via the low melting point bonding material. By joining, the heat generated from the electrode when the lamp is lit can be radiated well.

  According to the cold cathode fluorescent lamp of the fourth aspect, a highly reliable cold cathode fluorescent lamp can be provided by using the electrode mount as described above.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of an embodiment of a cold cathode phosphor lamp of the present invention.

  The cold cathode fluorescent lamp 1 includes a glass bulb 2, a phosphor film 3, an electrode mount 4, and a discharge medium.

  The glass bulb 2 is a straight tube and is an airtight container whose both ends are sealed with an electrode mount 4 via a bead glass 5. The glass bulb 2 has a total length of 300 mm, an outer diameter of 3.4 mm, and an inner diameter of 2.4 mm.

The phosphor film 3 is deposited and formed on the inner surface of the glass bulb 2 with a film thickness of 10 to 30 μm. The phosphor film 3 is formed by applying phosphor slurry to the inner surface of the bulb 2 and then sequentially drying and firing. The phosphor slurry is composed of three types of phosphors including a red phosphor (Y ₂ O ₃ : Eu), a green phosphor (LaPO ₄ : Ce), and a blue phosphor (BaMg ₂ Al ₁₀ O ₁₇ : Eu). Contains a wavelength phosphor, a binder (for example, alumina), a dispersant (for example, a carboxylic acid type dispersant), a thickener (for example, nitrocellulose), and a solvent (for example, butyl acetate). To be stirred.

  The discharge medium is enclosed in the glass bulb 2 and is composed of a mixed rare gas of mercury and Ne—Ar (composition ratio: Ne / Ar = 95 mol% / 5 mol%, enclosure pressure: 60 Torr). The amount of mercury enclosed is 4.2 to 7.0 mg.

  The electrode mount 4 is composed of an electrode 6 and an introduction wire 7, and a bead glass 5 is attached to the introduction wire 7, which is inserted into both ends of the glass bulb 2 and heated to be sealed.

  Hereinafter, the electrode 6 and the lead-in wire 7 constituting the electrode mount 4 will be described with reference to FIG. FIG. 2 is an enlarged view of a main part of the electrode mount 4 shown in FIG.

  The electrode 6 is a cylindrical housing and is joined to the lead-in wire 7 via a low melting point joining material 8. The electrode 6 is made of molybdenum having a melting point of 2623 ° C. and a thermal conductivity of 138 W / (m · K), or tungsten having a melting point of 3422 ° C. and a thermal conductivity of 174 W / (m · K). The dimensions of the electrode 6 are an outer diameter of 2.1 mm, a total length of 5.0 mm, and a bottom side surface thickness of 0.1 mm.

  The low melting point bonding material 8 is nickel having a melting point of 1455 ° C. and a thermal conductivity of 90.7 W / (m · K), iron having a melting point of 1535 ° C. and a thermal conductivity of 80.2 W / (m · K), or And a Ni—Fe alloy having a melting point of 1450 ° C. and a thermal conductivity of 16.8 W / (m · K).

  The lead-in wire 7 includes a sealing pin 9 and an external lead wire 10 in this order from the side joined to the electrode 6.

  A bead glass 5 is attached to the sealing pin 9 and sealed to the glass bulb 2. Further, the sealing pin 9 is bonded to the electrode 6 via the low melting point bonding material 8, and in this embodiment, the bonding surface between the sealing pin 9 and the electrode 6 is flush. It is joined. The sealing pin 9 is made of the same metal material as the electrode 6 described above.

The external lead wire 10 includes a core wire 10 a and a coating layer 10 b that covers the core wire 10 a, and is joined to the sealing pin 9 via the welded portion 11. The core wire 10a is made of an Fe—Ni alloy having a melting point of 1450 ° C. and a linear expansion coefficient of 6.4 to 7.3 × 10 ⁻⁶ / ° C. On the other hand, the coating layer 10b is made of Cu having a melting point of 1083 ° C. and a linear expansion coefficient of 16.0 to 17.0 × 10 ⁻⁶ / ° C.

  The welded portion 11 is a weld ball formed when one end of the external lead wire 10 is heated and melted and fused and joined to the sealing pin 9. The dimension of the welded portion 11 is 0.3 mm in length in the tube axis direction. That's it. The welded portion 11 is formed so as to cover the core wire melting portion 11a and the core wire melting portion 11a by melting the core wire 10a of the external lead wire 10 in order from the sealing pin 9 side. And a coating layer melting part 11b. The melted cores 10a and the coating layer 10b are not diffused and alloyed with each other, and the melted portions 11a and 11b are provided independently. In the coating layer melting part 11b, the compounding amount of the Cu component of the coating layer 10b that is not melted is 20 wt% or more with respect to the entire coating layer melting part 11b.

  Below, an example of the manufacturing method of the electrode mount 4 shown in FIG. 2 is demonstrated using FIG. 3A to 3E are process diagrams schematically showing a method for manufacturing the electrode mount shown in FIG.

  First, one end of the external lead wire 10 is heated and melted by burner heating or the like, and this is pressurized and welded to the sealing pin 9 (FIG. 3A) to produce the lead wire 7 having the welded portion 11 ( FIG. 3 (b)). At this time, as shown in FIG. 3B, the structure of the welded portion 11 is such that the melted core wire 10a of the external lead wire 10 and the coating layer 10b are not alloyed, and the core wire melting portion 11a and the coating layer melting portion. Welding (for example, resistance welding) is performed in a short time at a high temperature so that 11b is arranged independently.

  Next, after the low melting point bonding material 8 is disposed between the electrode 6 and the lead-in wire 7 (FIG. 3C), the electrode 6, the low-melting point bonding material 8 and the lead-in wire 7 are brought into contact with each other to obtain the low melting point The bonding material 8 is heated to its melting point temperature, and only the bonding material 8 is melted (FIG. 3D). Then, in a state where the low melting point bonding material 8 is melted, the electrode 6 and the lead-in wire 7 are pressed, and the low melting point bonding interposed so that the bonding surface of the electrode 6 and the sealing pin 9 is flush with each other. Joining is performed while extruding the material 8 (FIG. 3E).

  Thus, the electrode mount 4 of this embodiment is produced.

  According to the electrode mount 4 of the embodiment, it is generated from the electrode 6 when the lamp 1 is lit by joining the electrode 6 and the sealing pin 9 so as to be flush with each other via the low melting point bonding material 8. Heat can be radiated efficiently, and damage and performance degradation due to temperature rise during use can be suppressed.

  Further, the welded portion 11 of the lead wire 7 constituting the electrode mount 4 is prepared so that the melted core wire 10a and the coating layer 10b do not alloy with each other, so that the Cu component of the molten coating layer 10b becomes a sealing pin. 9 can be made difficult to contact. Thereby, the crack to the surface and the inside of the welding part 11 which generate | occur | produces from the location which the melt | dissolved Cu component contacted the sealing pin 9 can be reduced, and joint strength can be aimed at.

  Furthermore, according to the cold cathode fluorescent lamp 1 of the present embodiment using this electrode mount 4, the use of the electrode mount 4 with excellent heat dissipation can avoid a decrease in the performance of the lamp 1. A highly reliable cold cathode fluorescent lamp 1 can be provided.

(Other embodiments)
In the said embodiment, although demonstrated using the electrode mount 4 in which the electrode 6 and the sealing pin 9 were joined in the same plane, even if the sealing pin 9 and the electrode 6 are not contacting other than this, the electrode 6 It is also possible to join via the low melting point bonding material 8 so that the distance L between the sealing pin 9 and the sealing pin 9 is within 0.05 mm (see FIG. 4). Even in this form, similarly to the above-described embodiment, the heat generated from the electrode 6 when the lamp 1 is turned on can be efficiently radiated, and damage and deterioration in performance due to temperature rise during use can be suppressed.

Next, examples of the present invention and evaluation results thereof will be described.
Examples 1-2 and Comparative Examples 1-7
The electrode mount 4 having the configuration shown in FIG. 2 in which the electrode 6 and the sealing pin 9 were joined in a flush manner was produced.

  In the electrode mount 4 of FIG. 2, an electrode mount was prepared so that the distance between the electrode 6 and the sealing pin 9 was 0.05 mm, and this was taken as Example 2.

  In the electrode mount 4 shown in FIG. 2, the electrode mount is mounted so that the distance between the electrode 6 and the sealing pin 9 is 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, and 1.0 mm. Each was produced and these were made into Comparative Examples 1-6 in order.

  In the electrode mount 4 of FIG. 2, an electrode mount having a welded portion formed by alloying the melted core wire 10 a and the coating layer 10 b was produced.

  About the electrode mount of Examples 1-2 and Comparative Examples 1-6, the tube wall temperature of the electrode 6 was measured using the thermocouple thermometer (made by FLUKE), and the result was shown in Table 1.

  For the electrode mounts of Example 1 and Comparative Example 7, the tensile strength of the welded portion 11 was measured by applying a load in the tube axis direction while holding the sealing pin 9 and the external lead wire 10, and the results are shown in Table 2. It was.

Furthermore, 30 electrode mounts of Example 1 and Comparative Example 7 were prepared, and the same tensile test as above was performed on these, and the electrode mount in which the welded part 11 was detached from the sealing pin 9 was defective. The number of defects was measured and the results are shown in Table 3.

  As apparent from Table 1, Example 1 in which the distance between the bottom surface of the electrode 6 and the end surface of the sealing pin 9 is 0 mm (that is, the joint surface is flush), the electrode 6 and the sealing pin 9 are in contact with each other. In Example 2 in which the separation distance (distance between the bottom surface of the electrode 6 and the end surface of the sealing pin 9) is 0.05 mm, the tube wall temperature of the electrode 6 is 100 to 104 ° C. Heat generated from the electrode 6 can be efficiently dissipated, and damage and performance degradation due to temperature rise during use can be suppressed.

  Further, as apparent from Table 2, in Example 1, the tensile strength of the welded portion 11 is 13.5 to 11.6 kgf, whereas in Comparative Example 7, it is 13.5 to 6.0 kgf. Thus, the joint strength of the welded portion 11 of Example 1 is improved.

  As is apparent from Table 3, in Example 1, the welded part 11 does not fall off from the sealing pin 9, and the number of defects is significantly reduced. Therefore, the welding part 11 of Example 1 suppresses that the Cu component of the fuse | melted coating layer 10b contacts the sealing pin 9 by suppressing alloying with the melted core wire 10a and the coating layer 10b. In addition, the welded portion 11 has excellent bonding strength, and can provide the highly reliable electrode mount 4.

Sectional drawing which shows the structure of the cold cathode fluorescent lamp which concerns on embodiment of this invention. The principal part enlarged view of the electrode mount shown in FIG. Process drawing which shows the manufacturing method of the electrode mount shown in FIG. 2 with a typical cross section. The principal part enlarged view which shows the modification of the electrode mount shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cold cathode fluorescent lamp, 2 ... Glass bulb, 3 ... Phosphor film, 4 ... Electrode mount, 5 ... Bead glass, 6 ... Electrode, 7 ... Lead wire, 8 ... Low melting-point bonding material, 9 ... Sealing pin, DESCRIPTION OF SYMBOLS 10 ... External lead wire, 10a ... Core wire, 10b ... Coating layer, 11 ... Welding part, 11a ... Core wire melting part, 11b ... Coating layer melting part

Claims (4)

An electrode composed of a metal material having a melting point of 2000 ° C. or higher;
A lead wire joined to the electrode via a low melting point bonding material made of a metal material having a melting point of 1800 ° C. or lower, and bonded so that at least a part of the electrode is in contact with the electrode via the low melting point bonding material And a sealing member made of the same metal material as that of the electrode, and an external lead wire joined to the sealing member via a welding portion and having a core wire and a coating layer covering the core wire Lines and;
An electrode mount comprising:   2. The electrode mount according to claim 1, wherein the welded portion includes a core wire melting portion formed by melting the core wire of the external lead wire and a coating layer melting portion formed by melting the coating layer. An electrode composed of a metal material having a melting point of 2000 ° C. or higher;
An introduction line joined to the electrode through a low melting point bonding material composed of a metal material having a melting point of 1800 ° C. or less, and is in contact with the electrode within a distance of 0.05 mm or less. Without being bonded through the low-melting-point bonding material, and a sealing member made of the same metal material as the electrode, and a cover that is bonded through the sealing member and the welded portion to cover the core wire and the core wire An introduction line having a layer;
An electrode mount comprising: A glass bulb sealed at both ends;
The electrode mount according to any one of claims 1 to 3, which is sealed at both ends of the glass bulb;
A phosphor film deposited on the inner surface of the glass bulb;
A discharge medium enclosed in the glass bulb;
A cold cathode fluorescent lamp comprising:

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