KR100537571B1 - Discharge tube - Google Patents

Abstract

The total length of the discharge tube is shortened and connection failure is prevented.

An electrode assembly 10 having an introduction line 1 and a cup-shaped electrode 3, a glass tube 7 in which the electrode assembly 10 is fixed at both ends and filled with a gas for discharge therein, and a glass tube ( A fluorescent film 9 is coated on the inner surface 7a of 7) and emits visible light upon irradiation with ultraviolet rays generated by the discharge between the electrodes 3. The lead wire 1 has a lead portion 18 disposed outside both ends of the glass tube 7 and a embedding portion smaller in diameter than the lead portion 18 and sealed inside the glass tube 7 together with the electrode 3. Since the part 19 is provided and the raised part is not formed in the diameter reduction part 6 formed between the embedding part 19 and the lead-out part 18, the outer lead 8 can be firmly connected. At the same time, the overall length of the discharge tube can be shortened.

Description

Discharge tube {DISCHARGE TUBE}

The present invention relates to a discharge tube having a pair of electrodes, particularly a discharge tube capable of shortening the total length by reducing the non-light emitting region.

BACKGROUND OF THE INVENTION Cold cathode discharge tubes in which a pair of electrodes are disposed to face each other inside a glass tube filled with a rare gas and mercury vapor, and a fluorescent film is coated on the inner wall of the glass tube have been widely used as a light source for a backlight of a liquid crystal display. One end of the lead wire is connected to the pair of electrodes of the cold cathode discharge tube, and the other end of the lead wire is led outward from both ends of the glass tube. When a voltage is applied between the pair of electrodes, electrons are emitted from one electrode, and electrons collide with mercury atoms in the glass tube to generate ultraviolet rays. This ultraviolet-ray converts a wavelength into visible light in the fluorescent film formed in the inner wall of a glass tube.

The conventional cold cathode discharge tube 40 shown in FIG. 3 has a cup shape fixed to the lead line 11 and the lead line 11 in which the first lead line member 14 and the second lead line member 15 are fused together. The electrode assembly 20 shown in Fig. 4 (c) having the electrode 3, the glass tube 7 having the electrode assembly 20 fixed to both ends and filled with a gas for discharging therein, and the glass tube 7 ) Outside of the outer lead 8 connected to the lead portion 28 of the lead line 11 and the inner surface 7a of the glass tube 7 and irradiated with ultraviolet rays generated by the discharge between the electrodes 3. And a fluorescent film 9 that emits visible light. The lead wire 11 includes a lead portion 28, a buried portion 29 formed in the glass tube 7, and a coupling portion 16 that connects the lead portion 28 and the embedded portion 29.

In manufacturing the cold cathode discharge tube 40, first, a first lead wire constituting member 14 made of nickel having excellent solderability and a tungsten second lead constituting member 15 made of tungsten having excellent glass fusion are fused. A lead line 11 shown in Fig. 4A, a glass bead 2 formed in a cylindrical shape, and a nickel electrode 3 are prepared. The diameters of the first and second lead wire component members 14 and 15 are substantially the same. Next, as shown in FIG. 4B, the second lead wire constituting member 15 of the lead wire 11 is inserted into the hole 2a of the glass bead 2, and the protrusion 11a is inserted into the glass bead 2. ), The glass beads 2 are fused to the second lead wire constituting member 15. The hole 2a of the glass bead 2 has a diameter smaller than that of the engaging portion 16 and larger than that of the second lead wire constituting member 15. The welding position is set. Thereafter, as shown in FIG. 4C, the electrode assembly 20 is formed by welding the tip 11b of the protrusion 11a to the outer bottom surface 3a of the electrode 3 to form a cylindrical glass tube ( The electrode assembly 20 is disposed at both ends of the 7). After filling the glass tube 7 with a gas for discharge containing rare gas and mercury vapor, and then fusion of the glass bead 2 to the glass tube 7, as shown in FIG. 4 (d), the electrode 3 and buried The part 29 is sealed in the glass tube 7, and the coupling part 16 and the lead-out part 28 are brought out of the glass tube 7. After the lead portion 28 is cut to an appropriate length, the outer lead 8 is soldered and fixed, and the cold cathode discharge tube 40 shown in FIG. 3 is formed.

In the cold cathode discharge tube 40, since the first and second lead wire constituent members 14 and 15 have substantially the same diameter, when these are welded together, as shown in FIG. It is formed in the engaging portion 16 larger than the diameter of the first and second lead wire constituting members (14, 15). In the case of nickel and tungsten having a diameter of about 0.8 mm, the length L of the coupling portion 16 shown in Fig. 4A is about 0.6 mm. For this reason, when connecting the outer lead 8 to the lead-out part 28, as shown in FIG.4 (d), it is not located in the coupling part 16 but in the position away from the glass tube 7 and the coupling part 16. Since the lead 8 must be soldered and fixed, the cold cathode discharge tube 40 can not be miniaturized. Since this coupling part 16 is a non-light emitting area | region, so to speak, when the coupling part 16 is large, luminous efficiency will fall. In order to reduce the non-light emitting area, it is also possible to solder and fix the outer lead 8 to the ridge of the coupling portion 16, but the coupling portion 16 has a curved shape and an irregular shape. Fixability is also bad, and the external lead 8 is easy to peel off by external force. Therefore, sufficient strength of the connection between the external lead 8 and the lead portion 28 is not obtained, resulting in connection failure.

Therefore, an object of the present invention is to provide a discharge tube that can reduce the size of a non-light emitting area and to reduce the size thereof. In addition, an object of the present invention is to provide a discharge tube that strengthens the connection between the discharge tube and the external lead to prevent connection failure.

The discharge tube according to the present invention includes an electrode assembly (10) having a metal lead wire (1) and an electrode (3) fixedly attached to the lead wire (1), and the electrode assembly (10) is fixed at both ends and inside thereof. The glass tube 7 filled with the gas for discharge, and the fluorescent film 9 which coat | covers the inner surface 7a of the glass tube 7, and emits visible light by irradiation of the ultraviolet-ray generate | occur | produced by the discharge between the electrodes 3, ). In the present invention, the lead wire 1 has a lead portion 18 formed on the outside of both ends of the glass tube 7 and a diameter smaller than the lead portion 18 and sealed in the glass tube 7 like the electrode 3. The embedding part 19 and the diameter reduction part 6 formed between the embedding part 19 and the lead-out part 18 are provided.

The lead wire 1 formed by welding two metal members having different diameters includes a lead portion 18, a buried portion 19 having a smaller diameter than the lead portion 18, a lead portion 18, and a buried portion 19. ) Is provided with a diameter reducing portion (6) for connecting. In the diameter reduction part 6, the metal melted at the time of fusion | melting is not raised, and the whole length of a discharge tube can be shortened. In other words, when the lead wire is connected to the lead wire 1, the lead wire 1 can be connected to the diameter reducing part 6 formed at the position closest to the glass tube 7, so that the non-light emitting area can be made small, sufficient light emission amount can be ensured, and the discharge tube can be miniaturized. Can be planned. Further, when the lead wire is connected to the lead wire 1, the lead wire can be firmly and reliably connected to the diameter reducing part 6, so that a poor connection between the lead wire and the diameter reducing part 6 does not occur after the connection.

In the embodiment of the present invention, the diameter reducing portion 6 is formed on the outside of the glass tube 7 and is formed in the tapered or stepped shape having a smaller diameter from the lead portion 18 toward the buried portion 19. . The embedding length A of the diameter reduction part 6 into the glass tube 7 inside is 0.5 mm or less, and the difference of the diameter of the lead-out part 18 and the embedding part 19 is 0.2-3.0 mm. Moreover, it has the outer lead 8 connected to the lead wire 1 outside the glass tube 7, and the outer lead 8 is fixedly attached to the lead-out part 18 or the diameter reduction part 6 of the lead wire 1. As shown in FIG. The embedding portion 19 is made of tungsten, and the lead portion 18 is made of nickel.

Embodiment

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the discharge tube which concerns on this invention is described in FIG.

The cold cathode discharge tube 30 according to the present embodiment shown in FIG. 1 includes an electrode assembly 10 having a metal lead wire 1 and a cup-shaped electrode 3 fixedly attached to the lead wire 1, and an electrode. Glass tube 7 having assembly 10 fixed at both ends and filled with gas for discharge therein, outer lead 8 connected to lead line 1 outside glass tube 7, and inner surface of glass tube 7 A fluorescent film 9 which covers the 7a and is irradiated with ultraviolet rays generated by the discharge between the electrodes 3 to emit visible light is provided. A cylindrical glass bead 2 is fused to the metal lead line 1 of the electrode assembly 10, and the electrode 3 is sealed in the glass tube 7 by the connection between the glass bead 2 and the glass tube 7. do.

In the present invention, the lead line 1 has a lead portion 18 formed on the outside of both ends of the glass tube 7 and a diameter smaller than the lead portion 18 and sealed in the glass tube 7 like the electrode 3. And an external lead 8, which is a lead wire, is connected to the diameter reduction portion 6 and the lead-out portion 18 which are coupled to the embedding portion 19. For this reason, it differs from the conventional cold cathode discharge tube 40 shown in FIG. 3 in which the external lead 8 was connected away from the glass tube 7, and in this embodiment, the whole length of the cold cathode discharge tube 30 can be shortened.

The difference between the diameters of the lead portion 18 and the buried portion 19 is 0.2 to 3.0 mm. If the difference in diameter is less than 0.2 mm, a portion having a larger diameter than that of the lead portion 18 is formed in the diameter reduction portion 6, and if it exceeds 3.0 mm, the taper angle of the diameter reduction portion 6 becomes a steep slope. In either case, the connection between the diameter reduction part 6 and the external lead 8 is inferior.

In the manufacturing method of the said cold cathode discharge tube 30 which concerns on this embodiment, the 2nd tungsten-made 2nd tungsten whose diameter is smaller than the 1st lead-in constituent member 4 and the 1st lead-in constituent member 4 made from nickel initially, The lead wire constituting member 5 is fused to form a lead wire 1 shown in Fig. 2A.

Since the connection of the outer lead 8 to the lead wire 1 is performed by soldering fixation, the first lead wire constituent member 4 uses nickel which is excellent in solderability. As the second lead wire constituting member 5 to which the glass beads 2 are fused, tungsten excellent in fusion with glass is used. For this reason, although the diameter reduction part 6 which is the connection part of the 1st and 2nd lead wire structural members 4 and 5 becomes a metal which mixed nickel and tungsten, the 1st lead wire structural member 4 made from nickel is Compared with the tungsten second lead wire constituting member 5, since the diameter is large and the melting point is low, it contains a large amount of nickel. The diameter reducing portion 6 is not formed by being raised, but is formed in a tapered shape in which the diameter gradually decreases from the first lead line constituent member 4 to the second lead line constituent member 5. The diameter is, for example, about 0.8 mm for the first lead wire member 4 and about 0.5 mm for the second lead wire member 5. In addition, the diameter reduction part 6 may be formed in the step shape by welding the tip of the first lead wire constituting member 4 to the same diameter as that of the second lead wire constituting member 5 in advance. When formed in a stepped form, the adhesion between the diameter reducing portion 6 and the outer lead 8 is increased, and connection failure can be completely prevented.

The lead wire 1 is inserted into the hole 2a of the glass bead 2 from the second lead wire constituent member 5 side, and as shown in Fig. 2 (b), the protrusion 1a of the lead wire 1 is glass. Protrude from the beads (2). On the other hand, when the glass bead 2 is inserted into the lead line 1, the lead line 1 may be vertically disposed so that the first lead line constituent member 4 is lowered, and the glass bead 2 may be inserted from above. Since the diameter of the hole 2a formed in the glass bead 2 is smaller than the diameter of the first lead-in structural member 4 and slightly larger than the diameter of the second lead-in structural member 5, the glass bead 2 has a diameter. It hangs on the reduction part 6. Since the glass bead 2 is shorter than the second lead wire constituent member 5, when the lead wire 1 is inserted into the glass bead 2, the second lead wire constituent member 5 slightly protrudes from the glass bead 2. To form a projection 1a having a length of 0.5 to 30 mm.

Next, as shown in FIG.2 (c), the tip 1b of the protrusion part 1a is welded to the outer bottom surface 3a of the nickel electrode 3 formed in cup shape. The tip 1b of the protrusion 1a is brought into contact with the outer bottom surface 3a of the electrode 3, and a current is flowed therebetween to weld them. At this time, since the glass beads 2 are not fused to the lead line 1, even if heat generated during welding is transferred to the glass beads 2, cracks due to the difference in the coefficient of linear expansion between the metal and the glass may be generated. 2) does not occur. For this reason, the length of the protrusion part 1a only needs to ensure the minimum length required for good welding, and the electrode 3 is welded after the glass bead 2 and the lead wire 1 are fused. This can be set shorter than the projection 11a of the conventional method shown in FIG. For example, in order to prevent cracking of the glass beads 2, although the length of the conventional protrusion 11a requires about 0.7 mm even at the minimum, in this embodiment, the length of the protrusion 1a can be set to about 0.2 mm. have. By welding the lead wire 1 and the electrode 3, the glass beads 2 are sandwiched between the diameter reduction part 6 and the electrode 3, and do not fall out from the lead wire 1. Thereafter, the glass beads 2 are fused to the second lead wire constituting member 5, and the electrode assembly in which the lead wire 1, the glass bead 2, and the electrode 3 are integrally fixed to the lead wire 1 shown in FIG. 10) form.

The electrode assembly 10 is disposed in a cylindrical glass tube 7 covered with a fluorescent film 9 on an inner surface 7a. The electrode assembly 10 is disposed coaxially at both ends of the glass tube 7 with the electrodes 3 inwards in the state in which the glass tube 7 is inserted into the sealable chamber (container). The chamber is then sealed and filled in the glass tube 7 with a discharge gas consisting of one or two or more rare gases of neon gas, argon gas and xenon gas and metal vapor such as mercury vapor at a pressure of about 5.3 to 13 kPa. do. Both ends of the glass tube 7 filled with the gas for discharge and the glass beads 2 are heated by an electric furnace provided in the chamber, and the glass beads 2 are fused to the glass tube 7 so that the amount of the glass tube 7 is reduced. Occlusion the tip. As a result, the electrode 3 is sealed in the glass tube 7, and the embedding portion 19 of the lead wire 1 is formed in the glass tube 7. In addition, the diameter reduction portion 6 and the lead-out portion 18 are formed outside the glass tube 7, and as shown in FIG. 2E, the diameter reduction portion 6 has a portion embedded in the glass tube 7. The embedding length A is 0.5 mm or less.

Finally, after cutting out the front end side of the lead-out part 18 arranged outside the glass tube 7, the outer lead 8 is fixed to the lead-out part 18 and the diameter reduction part 6 by soldering. Since the outer lead 8 can be connected to the diameter reduction part 6 which adjoins the glass tube 7, the total length of the cold cathode discharge tube 30 can be shortened.

As described above, in the present invention, the discharge tube can be miniaturized, and the connection failure between the discharge tube and the external lead can be prevented and the strength and durability of the discharge tube can be improved.

1 is a cross-sectional view showing an embodiment of a discharge tube according to the present invention;

2 is a cross-sectional view showing a manufacturing method of a discharge tube according to the present invention;

3 is a cross-sectional view showing an embodiment of a conventional discharge tube;

4 is a cross-sectional view showing a manufacturing method of a conventional discharge tube.

<Explanation of symbols for main parts of the drawings>

1: lead line 1a: protrusion

1b: Tip 2: Glass Bead

2a: hole 3: electrode

3a: outer bottom surface 4: first lead wire constituent members

5: second lead wire constituent member 6: diameter reducing portion

7: glass tube 7a: inner surface

8: outer lead 9: fluorescent film

10: electrode assembly 18: derivation unit

19: buried portion 30: cold cathode discharge tube

A: Buried length

Claims (6)

An electrode assembly having a lead wire made of metal and an electrode fixedly attached to the lead wire, a glass tube in which the electrode assembly is fixed at both ends and filled with a gas for discharging therein, and coated on an inner surface of the glass tube and between the electrodes A fluorescent film that emits visible light upon irradiation of ultraviolet rays generated by the discharge of the light source, wherein the lead-in line is formed on the outside of both ends of the glass tube, and has a diameter smaller than that of the lead-out part and is similar to the electrode. In the discharge tube is provided with a buried portion sealed in the glass tube, the buried portion is formed of a material different from the lead portion, A tapered diameter reducing portion is formed between the buried portion and the lead-out portion, the diameter of which decreases in diameter from the lead-out portion toward the buried portion, and the glass beads hung on the diameter reducing portion are fused to the glass tube. discharge pipe. The discharge tube according to claim 1, wherein the buried portion is made of tungsten, the lead portion is made of nickel, and the diameter reducing portion is a mixed metal of nickel and tungsten. The discharge tube according to claim 1 or 2, wherein the discharge tube has an outer lead connected to the lead wire outside the glass tube, and the outer lead is fixedly attached to a lead portion or a diameter reduction portion of the lead wire. The discharge tube according to claim 1 or 2, wherein the embedding length into the glass tube inside the diameter reducing portion is 0.5 mm or less. The discharge tube according to claim 1 or 2, wherein a difference between the diameters of the lead portion and the buried portion is 0.2 to 3.0 mm. delete