JP2002157975A - Discharge tube and method of manufacturing discharge tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent contact failure by increasing connecting strength of discharge tube and external leads, and to shorten the total length of the discharge tube. SOLUTION: This discharge tube is provided with electrode assemblies 10 having lead-in wires 1 and electrodes 3, a glass tube 7 for fixing the electrode assemblies 10 to both ends, and filling discharge gas inside, and a fluorescent screen 9 covered with an inside surface 7a of the glass tube 7, and emitting visible radiation by receiving irradiation of an ultraviolet ray generated by discharge between the electrodes 3. The lead-in wires 1 are inserted into through holes 12a formed in metallic washer members 12, the washer members 12 are fixed to the lead-in wires 1, and the external leads 8 are fixed to the lead-in wires 1 in a state of abutting to the washer members 12 so that the external leads 8 and the lead-in wires 1 can be surely connected to prevent the contact failure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge tube having a pair of electrodes, and more particularly to a discharge tube and a method for manufacturing a discharge tube for making good connection with external leads.

[0002]

2. Description of the Related Art A cold-cathode discharge tube in which a pair of electrodes are opposed to 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 has been conventionally used in a liquid crystal display. Widely used as a light source for backlights. One end of an introduction wire is connected to a pair of electrodes of the cold cathode discharge tube, and the other end of the introduction wire is led out from both ends of the glass tube. When a voltage is applied between the pair of electrodes, electrons are emitted from one of the electrodes, and the electrons collide with mercury atoms in the glass tube to generate ultraviolet rays. This ultraviolet light is wavelength-converted to visible light by a fluorescent film formed on the inner wall of the glass tube.

[0003] A conventional cold cathode discharge tube (40) shown in FIG. 4 comprises an introduction wire (11) and an introduction wire obtained by fusing a first introduction wire member (14) and a second introduction wire member (15). An electrode assembly (20) shown in FIG. 5 (c) having a cup-shaped electrode (3) fixed to (11);
An electrode assembly (20) is fixed to both ends and a glass tube (7) filled with a discharge gas therein, and an introduction wire (1) outside the glass tube (7).
The external lead (8) connected to the lead-out part (28) of (1) and the inner surface (7a) of the glass tube (7) are covered with the ultraviolet rays generated by the discharge between the electrodes (3) and visible. A fluorescent film (9) for emitting light. The lead-in line (11) has a lead-out part (28) having a joint part (16) and a buried part (29) formed in a glass tube (7).
And

[0004] When manufacturing the cold cathode discharge tube (40), first, a first lead-in wire member made of nickel having excellent solderability.
The lead-in wire (11) shown in FIG. 5 (a) in which the (14) and the second lead-in wire member (15) made of tungsten having excellent glass fusing properties are fused.
, A glass bead (2) formed in a cylindrical shape, and an electrode (3) made of nickel are prepared. First and second lead-in members
The diameters of (14, 15) are substantially equal. Next, as shown in FIG. 5 (b), the second introduction line member (15) of the introduction line (11) is inserted into the hole (2a) of the glass bead (2), and the projection (11a) is inserted into the glass bead. While projecting from (2), the glass beads (2) are fused to the second introduction wire member (15). Thereafter, as shown in FIG. 5 (c), 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). The electrode assemblies (20) are arranged at both ends of the glass tube (7). After filling the glass tube (7) with a discharge gas containing a rare gas and mercury vapor, the glass beads (2) are removed from the glass tube (7).
5 (d), the electrode (3) and the buried portion (29) are sealed in the glass tube (7), and the lead-out portion (28) including the joint portion (16) is formed as shown in FIG. It is in a state of being led out of the glass tube (7). The external lead (8) shown in FIG.
By cutting out the lead-out part (28) connected by (13) and protruding from the external lead (8), the cold cathode discharge tube shown in FIG.
(40) is formed.

[0005]

The cold-cathode discharge tube (40)
In FIG. 5 (d), the external lead (8) is soldered and fixed at a right angle to the lead-out part (28), but in this case, sufficient connection strength cannot be obtained. When connecting the external lead (8) to the lead-out part (28), the lead-out part (28) is arranged inside the hook-shaped locking part (8a) formed on the external lead (8) shown in FIG. The inner surface (8b) of the locking portion (8a) and the lead-out portion (28) are connected by soldering. In the external lead (8), the inner surface (8b) of the locking portion (8a) facing the surface of the lead-out portion (28) is the only connection surface, and the lead-out portion (28) and the external lead (8) are firmly connected. The contact area is too small to connect. Therefore, in the cold cathode discharge tube (40), the connection strength of the external lead (8) to the discharge tube (7) cannot be sufficiently obtained, and the external lead (8) comes off from the lead-out portion (28) due to external force and comes into contact. Easy to cause defects. Further, since the contact area is small, soldering is difficult and workability is poor.

Further, the first and second lead-in members (14, 15)
Are substantially equal in diameter, so that when they are fused, as shown in FIG. 5 (a), the molten metal bumps become larger than the diameters of the first and second introduction wire members (14, 15). Department (16)
Formed. For this reason, the external lead (8)
As shown in FIG. 5 (d), the external lead (8) must be soldered to a position separated from the glass tube (7) and the coupling part (16), not to the coupling part (16), as shown in FIG. In addition, the overall length of the cold cathode discharge tube (40) cannot be reduced. Accordingly, it is an object of the present invention to provide a discharge tube and a method of manufacturing the discharge tube, in which the connection between the discharge tube and the external lead is strengthened to prevent poor connection. It is another object of the present invention to provide a discharge tube and a method for manufacturing the discharge tube, which can shorten the entire length.

[0007]

In a discharge tube according to the present invention, a metal lead-in (1) and an electrode fixed to the lead-in (1) are provided.
An electrode assembly (10) provided with (3), and a glass tube having the electrode assembly (10) fixed at both ends and filled with a discharge gas therein
(7), an inner surface (7a) of the glass tube (7) and an electrode (3)
A fluorescent film (9) that emits visible light when irradiated with ultraviolet light generated by the discharge between the electrodes. In the present invention, the lead wire is inserted into the through hole (12a) formed in the metal washer member (12).
(1) is inserted, and the external lead (8) is fixed to the lead-in wire (1) in a state of contact with the washer member (12).

The washer member (12) having an outer diameter larger than the diameter of the lead-in wire (1) is fixed to the lead-in wire (1) led out of the glass tube (7). When connecting the external lead (8) at right angles to the lead-in wire (1) outside of), the tip of the external lead (8) should be in contact with the main surface of the washer member (12), and soldering etc. Thereby, the external lead (8) can be easily fixed to the introduction wire (1). In addition, since the washer member (12) abuts against the external lead (8),
The mechanical strength at the connection between the (1) and the external lead (8) can be increased, and the poor electrical contact at the connection can be avoided.

In the embodiment of the present invention, the lead-in line (1) is
Embedded part (19) sealed in glass tube (7) with electrode (3)
The maximum diameter is larger than the buried part (19) and the glass tube (7)
A lead portion (18) formed outside the both ends of the lead portion, and a tapered reduced diameter portion (6) formed in the lead portion (18), and the reduced diameter portion (6) is attached to the external lead (8). Connected. The through-hole (12a) of the washer member (12) has a diameter larger than the buried portion (19) and smaller than the maximum diameter of the lead-out portion (18), and the outer edge of the through-hole (12a) is connected to the lead-out portion (18). Be abutted.

In the method for manufacturing a discharge tube according to the present invention, a first introduction wire member (4) and a second introduction wire member (5) having a smaller diameter than the first introduction wire member (4) are fused. And forming an introduction wire (1) having a reduced diameter portion (6), and inserting a second introduction wire member (5) into a hole (2a) formed in the glass beads (2). , A second lead-in member protruding from the glass beads (2)
(5) welding the electrode (3) to the hole of the glass beads (2)
Before or after inserting the second introduction wire member (5) into (2a), the introduction wire (1) is inserted into the through hole (12a) formed in the metal washer member (12), and the washer member ( 12) attaching the introduction wire (1), and fusing the glass bead (2) to the second introduction wire member (5), and introducing the introduction wire (1), the glass beads (2) and the electrode (3). ) To form an electrode assembly (10) integrally fixed, and an electrode assembly (10) at both ends of a cylindrical glass tube (7) having an inner surface (7a) coated with a fluorescent film (9). And a step of disposing the glass beads (2) and the glass tube (7) in a state where the reduced diameter portion (6) and the washer member (12) are arranged outside the glass tube (7).
Seal the electrode (3) inside (7) and bury the lead-in wire (1).
Forming (19) in the glass tube (7).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a discharge tube according to the present invention will be described below with reference to FIGS. A cold cathode discharge tube (30) according to the present embodiment shown in FIG. 1 has an electrode assembly (1) including a metal introducing wire (1) and a cup-shaped electrode (3) fixed to the introducing wire (1). 10), a glass tube (7) with the electrode assembly (10) fixed at both ends and filled with a discharge gas inside, and FIG. 6 connected to the lead-in (1) outside the glass tube (7). The outer lead (8) shown in Fig. 4 and the inner surface (7a) of the glass tube (7)
A fluorescent film (9) that emits visible light when irradiated with ultraviolet rays generated by the discharge in (3).

A cylindrical glass bead (2) is fused to the metal lead-in (1) of the electrode assembly (10), and the electrode is connected by connecting the glass bead (2) and the glass tube (7). (3) is sealed in the glass tube (7). The lead-in wire (1) sealed in the glass tube (7) together with the electrode (3) forms a buried portion (19), and the buried portion (1
An introduction line (1) having a maximum diameter larger than that of (9) and formed outside both ends of the glass tube (7) forms an outlet portion (18). The locking portion (8a) of the external lead (8) is connected to the tapered reduced diameter portion (6) formed as the lead-out portion (18), and is fixed by the solder (13). The difference between the maximum diameter of the lead-out part (18) and the diameter of the buried part (19) is 0.3 to 3 mm. If the difference in diameter is less than 0.3 mm, the bump having a larger diameter than the lead-out portion (18) will be
When the diameter exceeds 3 mm, the taper angle of the reduced diameter portion (6) becomes steep, and in any case, the connectivity between the reduced diameter portion (6) and the external lead (8) decreases.

In the present invention, when the external lead (8) is soldered, as shown in FIG. 1, a metal washer member (12) is used.
Between the external lead (8) and the glass tube (7). The washer member (12) is provided with a through hole (12a) at the center as shown in FIG. 3 (a), and the introduction line (1) is inserted into the through hole (12a) to insert the washer member (12) into the introduction line ( It is fixed to the derivation part (18) of 1).
The diameter of the through hole (12a) of the washer member (12) is
Since it is larger than the diameter and smaller than the maximum diameter of the outlet portion (18), when the washer member (12) is pressed against the reduced diameter portion (6) to fuse the glass beads (2) and the glass tube (7), a through hole is formed. (12a)
With the outer edge of the glass tube (7) in contact with the outlet (18)
A washer member (12) is fixed between the washer and the reduced diameter portion (6).
As a result, the external lead (8) can be soldered to the washer member (12) together with the lead-out part (18), so that the contact area for soldering is large and the lead-out part (8) is mechanically high in strength. 18) can be connected. Also, even if the cold cathode discharge tube (30) is used for a long time, the connection of the external lead (8) is not loosened and the electrical contact failure does not occur.

[0014] The cold cathode discharge tube (30) according to the present embodiment.
First, a first lead-in wire member made of nickel is used.
(4) and a second introduction wire member (5) made of tungsten having a diameter smaller than that of the first introduction wire member (4) are fused to form a reduced diameter portion (6).
The introduction line (1) shown in FIG.

Since the connection between the lead-out portion (18) of the lead-in wire (1) and the external lead (8) is performed by soldering, the first lead-in wire member (4) uses nickel which is excellent in solderability. I do. Further, a second introduction wire member (5) to which the glass beads (2) are fused.
Uses tungsten which has excellent adhesion to glass. For this reason, the reduced diameter portion (6), which is the connecting portion of the first and second introduction wire members (4, 5), is made of a mixed metal of nickel and tungsten. Element
(4) has a larger diameter and a lower melting point than the second lead wire member (5) made of tungsten, so that it contains much nickel. The reduced diameter portion (6) is formed in a tapered shape in which no bump is formed and the diameter gradually decreases from the first introduction wire member (4) to the second introduction wire member (5). There is no need to connect the external lead (8) to the lead-in wire (11) by avoiding the bumps of the joint (16) as in the conventional example of
In (30), the total length can be shortened.

For example, the diameter of the first lead wire member (4) is about 8 mm, and the diameter of the second lead wire member (5) is about 5 mm. In addition, the diameter of the reduced diameter portion (6) is formed in a step-like shape by preliminarily fusing only the tip of the first introduction wire member (4) to substantially the same diameter as the diameter of the second introduction wire member (5). May be.

As shown in FIG. 2B, the lead-in wire (1) is passed through the through-hole (12) of the washer member (12) from the side of the second lead-in member (5).
After passing through a), insert the lead wire (1) into the hole (2a) of the glass beads (2).
And the protrusion (1a) of the introduction wire (1) is projected from the glass bead (2) as shown in FIG. 2 (c). Like the through hole (12a) of the washer member (12), the diameter of the hole (2a) formed in the glass bead (2) is smaller than the diameter of the first introduction line member (4) and the second introduction line (4). Since it is larger than the diameter of the wire member (5), the washer member (12) and the glass beads (2) are reduced in diameter (6).
Locked by. Glass bead (2) is the second lead wire member (5)
Since the guide wire (1) is inserted into the glass bead (2), the second guide wire member (5) protrudes from the glass bead (2) because it is shorter than the glass bead (2). To form

Next, as shown in FIG. 2 (d), the tip (1b) of the protrusion (1a) is welded to the outer bottom surface (3a) of the cup-shaped nickel electrode (3). Tip (1b) of protrusion (1a)
And the outer bottom surface (3a) of the electrode (3) are brought into contact with each other. At this time, glass beads (2)
Is not fused to the introduction wire (1), so even if the heat generated during welding is transmitted to the glass beads (2), cracks due to the difference in linear expansion coefficient between the metal and the glass
Does not occur in (2). For this reason, the length of the protruding portion (1a) may be ensured by the minimum length necessary for performing good welding, and after the glass beads (2) and the introduction wire (1) are fused. The length can be set shorter than the protrusion (11a) of the conventional example shown in FIG. 5 for welding the electrode (3). For example, in order to prevent cracks in the glass beads (2), the length of the projection (11a) of the conventional example needs to be at least about 0.7 mm, whereas in the present embodiment, the length of the projection (1a) is The length can be reduced to about 0.2 mm. By welding the lead-in wire (1) and the electrode (3), the washer member (12) and the glass beads (2) are reduced in diameter by the reduced diameter portion (6) and the electrode.
It does not fall out of the lead-in line (1) because it is sandwiched between (3). Thereafter, when the glass beads (2) are fused to the second introduction wire member (5), the introduction wire (1), the glass beads (2) and the electrode (3) shown in FIG. Further, the electrode assembly (10) in which the washer member (12) is fixed between the reduced diameter portion (6) and the glass beads (2) can be formed.

The electrode assembly (10) has a fluorescent film (9) on the inner surface (7a).
Is placed in the coated cylindrical glass tube (7). With the glass tube (7) inserted in a sealable chamber (container), the electrode assembly (10) is coaxial with both ends of the glass tube (7) with the electrodes (3) facing inward. Be placed. Thereafter, the chamber is closed, and a discharge gas composed of one or more rare gases of neon gas, argon gas and xenon gas and metal vapor such as mercury vapor is supplied to the glass tube at a pressure of about 5.3 to 13 kPa. (7) Fill inside. Both ends of the glass tube (7) filled with the discharge gas and the glass beads (2) are heated by an electric furnace or the like provided in the chamber, and the reduced diameter portion (6) and the washer member (12) are heated by the glass tube ( 7) With the glass beads (2) fused to the glass tube (7) while being placed outside, the glass tube (7)
Close both ends. This allows the electrode (3) to be connected to the glass tube (7).
And a buried portion (19) of the lead-in wire (1) is formed in the glass tube (7). Also, the reduced diameter part (6) and the washer member
A lead portion (18) having (12) is formed outside the glass tube (7).

As shown in FIG. 2F, the external leads shown in FIG.
(8) is connected to the reduced diameter portion (6) in a state of contact with the washer member (12). That is, together with the reduced diameter portion (6) of the lead-out portion (18), the lead-out portion
The external lead (8) can also be soldered to the main surface of the washer member (12) fixed to (18), so that the external lead (8) can be easily connected to the lead-in wire (1). 1 and 2 (f) show a state in which the external lead (8) is connected only to the reduced diameter portion (6), but the width of the external lead (8) is larger than the length of the reduced diameter portion (6). At this time, the external lead (8) may be connected to the lead-out portion (18) other than the reduced diameter portion (6) together with the reduced diameter portion (6). Finally, by cutting out the lead-out portion (18) projecting outside the external lead (9), the cold cathode discharge tube (30) shown in FIG. 1 is formed.

In the above embodiment, before inserting the second introduction wire member (5) into the hole (2a) of the glass bead (2), the introduction wire (12) is inserted into the through hole (12a) of the washer member (12). Although the cold cathode discharge tube (30) for inserting 1) is shown, after forming the electrode assembly (10),
C having a notch (12b) in the through hole (12a) as shown in FIG.
A shaped washer member (12) may be attached to the lead-out portion (18).

[0022]

As described above, according to the present invention, the mechanical strength at the connecting portion between the discharge tube and the external lead can be increased and the contact failure can be prevented, so that the durability and reliability of the discharge tube can be improved. . Further, the overall length can be shortened and the size of the discharge tube can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a discharge tube according to the present invention.

FIG. 2 is a sectional view showing a method for manufacturing a discharge tube according to the present invention.

FIG. 3 is a plan view showing a washer member.

FIG. 4 is a sectional view showing a conventional discharge tube.

FIG. 5 is a sectional view showing a conventional method for manufacturing a discharge tube.

FIG. 6 is a plan view showing the tip of an external lead.

[Explanation of symbols]

(1) ・ ・ Introduction line, (1a) ・ ・ Protrusion, (1b) ・ ・ Tip,
(2) ・ ・ Glass beads, (2a) ・ ・ Hole, (3) ・ ・ Electrode,
(3a) ··· Outer bottom surface, (4) ··· First lead wire member,
(5) ・ ・ Second introduction wire member, (6) ・ ・ Reduced diameter part,
・ Glass tube, (7a) ・ ・ Inner surface, (8) ・ ・ External lead,
(8a) ··· Locking part, (8b) ··· Inner surface, (9) ··· Fluorescent film, (10) ··· Electrode assembly, (12) ··· Washer member,
(12a) ・ ・ Through hole, (12b) ・ ・ Notch, (13) ・ ・ Solder, (18) ・ ・ Derived part, (19) ・ ・ Buried part, (30) ・ ・
Cold cathode discharge tube,

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C012 AA08 MM01 MM07 5C035 HH05 5C043 AA12 AA17 AA18 CC09 CD01 DD17 DD20 DD22 EA09 5C235 HH05

Claims (4)

[Claims] An electrode assembly including a metal lead wire and an electrode fixed to the lead wire; a glass tube having the electrode assembly fixed at both ends and filled with a discharge gas therein;
A fluorescent film, which is coated on the inner surface of the glass tube and emits visible light when irradiated with ultraviolet light generated by the discharge between the electrodes, wherein a through hole formed in a metal washer member has A discharge tube, wherein the lead wire is inserted, and an external lead is fixed to the lead wire in a state of contact with the washer member. 2. The buried part sealed in the glass tube together with the electrode, the lead-in line has a maximum diameter larger than the buried part, and the lead-out parts are formed outside both ends of the glass tube. 2. A tapered diameter-reduced portion formed in a lead-out portion, wherein the diameter-reduced portion is connected to the external lead.
The discharge tube according to claim 1. 3. The through hole of the washer member has a diameter larger than the buried portion and smaller than a maximum diameter of the lead portion, and an outer edge of the through hole is in contact with the lead portion. Discharge tube as described. 4. a step of fusing a first introduction wire member and a second introduction wire member having a smaller diameter than the first introduction wire member to form an introduction wire having a reduced diameter portion; Inserting the second introduction wire member into a hole formed in the glass bead; welding the second introduction wire member protruding from the glass bead to an electrode; and inserting the second introduction wire member into the hole of the glass bead. A step of inserting the introduction wire into a through hole formed in a metal washer member before or after inserting the second introduction wire member, and attaching the washer member to the introduction wire; and Fused to the second introduction wire member,
Forming an electrode assembly in which the introduction wire, glass beads, and electrodes are integrally fixed; disposing electrode assemblies at both ends of a cylindrical glass tube having an inner surface coated with a fluorescent film; The glass bead and the glass tube are fused with the diameter portion and the washer member arranged outside the glass tube to seal the electrode in the glass tube and to embed the introduction wire in the glass tube. Forming the discharge tube in a tube.