JPH08250070A - Cold cathode fluorescent lamp and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide a cold cathode fluorescent lamp and a method of manufacturing this cold cathode fluorescent lamp wherein also reliability of air-tight sealing can be improved in addition to that a sealing form between a glass bulb and an electrode can be reformed by a simple constitution. CONSTITUTION: One electrode 3A is sealed in an end part 1a of a glass bulb 1 having an emitting layer 2 is an interval surface. This electrode 3A is constituted by a lead wire 31 comprising an inner lead 31a, sealed wire rod 31b and an outer lead 31c, cylindrical electrode part 32 fixed to the inner leads 31a and an air-tightly sealed glass bead 33 of coating the sealed wire rod 31b. Further, an external diameter of the glass bead 33 is set to a range of 50 to 80% an internal diameter of the glass bulb 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold cathode fluorescent lamp and a method for manufacturing the same, and more particularly to a cold cathode fluorescent lamp of a backlight unit applied to a liquid crystal display device, in which a glass bulb of an electrode capable of improving sealing work can be improved. The present invention relates to a sealing structure and a manufacturing method thereof.

[0002]

2. Description of the Related Art A conventional fluorescent lamp of this kind is shown in FIG.
As shown in FIG. 0, the electrode C is sealed and arranged at each end of the glass bulb B having the light emitting layer A on the inner surface. In particular, the electrode C is a lead wire composed of an inner lead C1, a sealing wire C2, an outer lead C3 and a glass bead D covering the sealing wire C2, and an inner lead C1.
It is composed of a mercury dispenser E fixed to. The dispenser E is formed, for example, by depositing powder of zirconium-aluminum alloy as a getter material and mercury-titanium alloy as a mercury supply means on the front and back surfaces of a metal plate such as nickel.

In this fluorescent lamp, the inside of the glass bulb B is replaced with, for example, neon-argon gas whose main component is neon, the glass bulb B and the glass beads D of the electrodes C are sealed, and then the high-frequency heating device is used. Mercury dispenser
It is completed by heating E, supplying the mercury released from it to the inner space of the glass bulb, and adsorbing the impure gas by the getter material.

When the fluorescent lamp having such a structure is applied to a backlight unit of a liquid crystal display device, since the outer diameter of the glass bulb B is as thin as 6 mm or less, the lamp brightness is high and a desirable display is obtained. It has the feature that it can be obtained.

[Problems to be Solved by the Invention]

By the way, this fluorescent lamp is manufactured, for example, as follows. First, as shown in FIGS. 11 to 12, an electrode C is arranged at the other end of a glass bulb B having an electrode sealed at one end, and a part of the outer peripheral portion of the glass bulb B (F ) Is heated by a gas burner. As a result, not only the glass bulb B but also the glass beads D are heated and softened through the glass bulb B, and the glass bulb B and the glass beads D are partially fused and temporarily fixed at the deformed portion F. It A communication portion G is formed between the glass bulb B and the glass bead D, as shown in FIG. Next, the glass bubble B is set in the exhaust device H, and the exhaust gas from the glass bulb is exhausted through the communicating portion G by the exhaust device H. After that, a predetermined amount of inert gas is filled in the glass bulb, and the communication part G is heated by a gas burner to hermetically fuse the glass bulb B and the glass bead D, and the cullet portion (exhaust device side). (The glass bulb part of) is disconnected. After that, by heating the mercury dispenser E with a high-frequency heating device, mercury is supplied to the internal space of the bulb, and the impure gas emitted due to the high-frequency heating is adsorbed by the getter material to cause a fluorescent lamp. Is manufactured.

However, when the electrode C is temporarily fixed to the other end of the glass bulb B, the outer diameter of the glass bead D is set to about 40% of the inner diameter of the glass bulb B.
The glass bulb B is largely deformed (F) due to the temporary fixing of both. Therefore, even if the gas burner reheats and softens the planned sealing portion after the exhaust work to perform the sealing work, the sealing portion of the glass bulb B becomes uneven, and the appearance (finished state) is significantly impaired. Not only is there a problem that the reliability of hermetic sealing is also affected.

Therefore, an object of the present invention is to improve the sealing form between the glass bulb and the electrode with a simple structure, and
It is an object of the present invention to provide a cold cathode fluorescent lamp that can improve the reliability of hermetic sealing and a manufacturing method thereof.

[0008]

SUMMARY OF THE INVENTION Therefore, in order to achieve the above-mentioned object, the present invention provides an electrode including a lead wire having a sealing wire and a glass bead covering the sealing wire at the end of a glass bulb. In a cold cathode fluorescent lamp in which a glass bead and a glass bulb are hermetically sealed while being arranged, the outer diameter of the glass bead is 50 to 80% of the inner diameter of the glass bulb.
The second invention of the present invention is set in the range of
The inner diameter of the glass bulb is set to 6 mm or less, and the third invention is that the glass bead is formed into a spherical shape or a columnar shape.

A fourth invention of the present invention is to place a lead wire having a sealing wire and an electrode including a glass bead covering the sealing wire in a glass bulb and heating the glass bulb to heat the glass bulb. Before sealing the glass beads with the glass beads, the outside diameter of the glass beads is set within a range of 50 to 80% of the inside diameter of the glass bulb.
The invention is characterized in that the glass beads have a spherical or columnar shape.

[0010]

According to the above construction, the outer diameter of the glass bead of the electrode is set to 50 to 80% of the inner diameter of the glass bulb. Therefore, when the both are hermetically sealed, the deformation amount of the glass bulb is Can be reduced. Therefore, the sealing form of the glass bulb can be improved, and the reliability of hermetic sealing can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to FIGS.
Will be described with reference to. In the figure, 1 is a glass bulb made of boro-silicate glass having a bulb inner diameter of about 3 mm, for example, and a light emitting layer 2 is formed on the inner surface thereof. The glass bulb 1 is made of lead glass, soda glass,
Low lead glass can also be used. The light emitting layer 2 is formed by mixing one kind of phosphor or a plurality of kinds of phosphor according to the purpose. Then, the end portion 1a of the glass bulb 1,
Electrodes 3A and 3B are arranged on 1b.

The electrodes 3A and 3B are basically the same, for example, a tubular electrode portion 32 is electrically and mechanically fixed (for example, welded) to the tip of the lead wire 31, and the lead wire 3 is used.
A glass bead 33 made of borosilicate glass is hermetically sealed in a portion close to the electrode portion 32 of No. 1, but the electrode portion 32 may be omitted and an inner lead described later may be used instead. A mercury dispenser can also be attached. The electrode portion 32 may have a tubular shape having openings at both ends, or may have a tubular shape in which one opening is closed (bottomed tubular shape) or the opening is reduced. .
In particular, the shape of the glass beads 33 in this electrode 3A is columnar, and its outer diameter d is equal to that of the glass bulb 1.
The inner diameter D is set to be 50 to 80%.

The lead wire 31 is basically an inner wire.
Lead 31a, sealing wire 31b, outer lead 31c
Are butt welded (end face welded). In this lead wire 31, the inner lead 31
The outer diameters D1, D2 and D3 of a, the sealing wire member 31b, and the outer lead 31c are set to satisfy the relationship of D1>D2> D3. For example, in this lead wire 31, a nickel wire having an outer diameter of 1.0 mm is used for the inner lead 31a, a kovar having an outer diameter of 0.6 mm is used for the sealing wire 31b, and an outer lead is used. A nickel wire having an outer diameter of 0.35 mm is used for each 31c, but it can be changed to another material, integrally machined from the same wire material, or the outer diameter can be changed appropriately. . Then, this fluorescent lamp is filled with a predetermined amount of inert gas and mercury by a method described later.

Next, a method of manufacturing this fluorescent lamp will be described with reference to FIGS. First, as shown in FIG. 3, one electrode 3A is located at one end 1a of a glass bulb 1 having an inner surface having a light emitting layer 2 and an inner diameter set to D. The outer diameter d of the glass bead 33 in the electrode 3A is set to d = 0.5D to 0.8D.

Then, as shown in FIG. 4, the end portion 1a of the glass bulb 1 is heated to hermetically seal the glass bulb 1 and the glass bead 33, and the other electrode 3B is placed inside the glass bulb 1. , A predetermined part (1b) from the other end 1c thereof
Insert and place up to. Then, part 1b of the glass bulb 1 is partially heated and deformed (4) to temporarily fix the other electrode 3B to the glass bulb 1. Specifically, the glass bead 33 of the other electrode 3B and the glass bulb 1 are partially fused and temporarily fixed. Therefore, as shown in FIG. 5 which is a cross section of FIG.
A communication portion 4A is formed in the other portions.

Next, as shown in FIG. 6, a mercury dispenser 5 is inserted and arranged in the glass bulb 1. still,
The dispenser 5 is constituted by, for example, depositing a getter material made of a zirconium-aluminum alloy on the surface of a nickel plate and a mercury alloy made of a mercury-titanium alloy on the back surface thereof. It is also possible to mix the above powders and deposit them on a nickel plate. Then, the glass bulb 1 is set on the head of the exhaust device 6 and the exhaust device 6 is driven. Then, the air, the impure gas, and the like inside the glass bulb 1 are discharged through the above-mentioned communicating portion 4A and the like. At this time,
By appropriately heating the glass bulb 1 (including the electrode and the mercury dispenser), the degassing process can be effectively performed. Then, the glass bulb 1 is filled from the exhaust device 6 with an inert gas, for example, neon-argon gas mainly containing neon gas so as to have a pressure of 60 to 70 Torr.

Next, as shown in FIG. 7, the glass bulb 1
The other end 1c is sealed and removed from the exhaust device 6. Then, the magnet 7 is moved from the dotted line position in the figure to the solid line position. As a result, the position of the mercury dispenser 5 is restricted to a predetermined part. Next, as shown in FIG.
The high frequency heating device 8 and the heater device 9 are set and driven at the portion where the mercury dispenser 5 is located.
Then, the mercury dispenser 5 is, for example, 800 to 900.
When heated to ℃, the mercury alloy is decomposed, and mercury is instantaneously released in a vapor state and supplied to the space inside the bulb through the communication portion 4A of the electrode 3B. At the same time, the impure gas is also released from the metal member forming the dispenser 5,
It is adsorbed by the getter material of the dispenser 5. Further, at this time, since the glass bulb portion containing the dispenser 5 is also heated by the heater device 9,
Mercury emitted from the dispenser-5 is the electrodes 3A, 3B.
It is reliably supplied to the space inside the glass bulb corresponding to the space.
In particular, if the glass bulb portion between the electrodes 3A and 3B is cooled, the condensation of mercury on the glass bulb portion in which the dispenser 5 is housed can be substantially eliminated. Next, the deformed portion 4 of the glass bulb 1 is heated again by a burner or the like to seal the glass beads 33 of the electrode 3B and the glass bulb 1 facing the glass beads 33 over the entire circumference. At the same time, as shown in FIG. 9, the other end portion of the glass bulb 1 (the mercury dispenser-
The glass bulb portion 5) is removed (separated) to complete the manufacture of the cold cathode fluorescent lamp.

The present inventors have found that the valve inner diameter D is 3 mm and 6 mm.
mm, the end of the glass bulb of 360 mm in length, 1.
An inner lead made of 0 mm nickel wire, a sealing wire made of kovar having an outer diameter of 0.6 mm, and an outer lead made of nickel wire were butt welded and a glass wire made of borosilicate glass was used as the sealing wire. In the above manufacturing method, an electrode formed by inserting and welding a nickel sleeve (electrode portion) having an inner diameter of 1.1 mm and a length of 5.0 mm into a lead wire that seals the lead is used. A cold cathode fluorescent lamp was manufactured by using the above method, and the relationship between the outer diameter of the glass bead and the various characteristics with respect to the inner diameter of the glass bulb was examined.

[0019]

[Table 1]

According to this result, the lamps NO1 and NO5
The outer diameter of the glass beads with respect to the inner diameter of the glass bulb is 42% and 40%, and the finished state of the sealed form is impaired. Other lamps have a good sealing morphology. Also, the lamps of NO1, 2, 5, and 6 have good starting characteristics, but the lamps of NO3 and 7 are
Although there is no problem in practical use, it is a little worse. But,
It is shown that the lamps of NO4 and 8 are deteriorated and cannot be put to practical use. Therefore, the outer diameter d of the glass bead
Is to be set within the range of 50 to 80% with respect to the inner diameter D of the glass bulb.

However, if the range is less than 20%, not only the sealing form is impaired but also the reliability of sealing is deteriorated. On the contrary, if it exceeds 80%, impurities in the valve during exhaust work are impaired. The exhaust speed of the gas is reduced and the starting characteristics are impaired. Therefore, deviation from that range is
Not preferred.

The present invention is not limited to the above-described embodiment. For example, a mercury dispenser encloses a predetermined amount of mercury in a glass capsule and wraps a metal wire such as a nichrome wire in the capsule, or a metal capsule. It is also possible to enclose a predetermined amount of mercury in. Further, the steps shown in FIGS. 6 to 9 can be performed in a state of being set in the exhaust device, and if the positioning is performed when the dispenser is placed in the glass bulb, the position regulation by the magnet can be omitted. . Further, the mercury getter material can be housed in the sleeve-shaped electrode portion.

[0023]

As described above, according to the present invention, the outer diameter of the glass beads of the electrode is 50 to 80 that of the inner diameter of the glass bulb.
%, It is possible to reduce the amount of deformation of the glass bulb at the time of hermetically sealing the both. Therefore, the sealing form of the glass bulb can be improved, and the reliability of hermetic sealing can be improved. In addition, if it is within the above range, it is possible to secure a communication portion between the glass bulb and the glass bead, which does not impair the exhaust work, so that a starting characteristic that does not hinder practical use can be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a side sectional view showing a state before the electrode is inserted into the glass bulb.

FIG. 4 to FIG. 9 are views for explaining the method of the present invention, and FIG. 4 is a side sectional view showing a state where electrodes are sealed and temporarily fixed.

5 is a cross-sectional view of FIG.

FIG. 6 is a side sectional view for explaining an exhaust process.

FIG. 7 is a side sectional view for explaining a position regulating process of the mercury dispenser in the glass bulb.

FIG. 8 is a side sectional view for explaining a high frequency heating process of the mercury dispenser.

FIG. 9 is a side sectional view for explaining a step of removing an unnecessary portion of the glass bulb.

FIG. 10 is a side sectional view of a conventional cold cathode fluorescent lamp.

FIG. 11 is a side sectional view for explaining a step of sealing an electrode in a glass bulb and an exhaust step.

12 is a cross-sectional view of the deformed portion of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass bulb 1a One end 2 Light emitting layer 3A, 3B Electrode 31 Lead wire 31a Inner lead 31b Sealing wire rod 31c Outer lead 32 Electrode part 33 Glass bead 4 (1b) Deformation part 4A Communication part 5 Mercury Dispenser 6 Exhaust device 7 Magnet 8 High frequency heating device 9 Heater device

Claims (5)

[Claims] 1. A cold cathode in which an electrode including a lead wire having a sealing wire and a glass bead covering the sealing wire is arranged at an end of a glass bulb, and the glass bead and the glass bulb are hermetically sealed. In the fluorescent lamp, the outer diameter of the glass beads is set in the range of 50 to 80% of the inner diameter of the glass bulb. 2. The cold cathode fluorescent lamp according to claim 1, wherein the inner diameter of the glass bulb is 6 mm or less. 3. The cold cathode fluorescent lamp according to claim 1, wherein the glass beads have a spherical or columnar shape. 4. An electrode including a lead wire having a sealing wire and a glass bead covering the sealing wire is placed in a glass bulb, and the glass bulb and the glass bead are sealed by heating the glass bulb. Prior to the step 1, the outer diameter of the glass beads is set within a range of 50 to 80% of the inner diameter of the glass bulb. 5. The method of manufacturing a cold cathode fluorescent lamp according to claim 4, wherein the glass beads have a spherical or columnar shape.