JPH07109748B2 - Fluorescent lamp manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a fluorescent lamp.

2. Description of the Related Art Recently, as a highly efficient compact fluorescent lamp that can be replaced with an incandescent light bulb in order to save energy, a compact fluorescent lamp with a ballast, a lighting tube, etc., and a screw base for an incandescent light bulb has been developed. It has been put to practical use.

The arc tube of such a small fluorescent lamp usually has a U shape or a double U shape in which the U shape is further bent, and is housed in a globe. In such a compact fluorescent lamp, the temperature of the arc tube inside the globe rises, and as a result the mercury vapor pressure in the arc tube becomes higher than the optimum value, and the efficiency of generating ultraviolet rays effective for light emission decreases, which in turn results in the luminous efficiency of the arc tube. There is a problem in that In order to solve such a problem, there is an amalgam method as one method of suppressing the increase in mercury vapor pressure due to the increase in temperature of the arc tube. Next, a fluorescent lamp adopting the amalgam system will be described with reference to FIG.

In FIG. 2, the arc tube 1 is housed in a globe 2. A ballast and a lighting tube (not shown) are housed in the case 3, and a screw-type base 4 is attached to the bottom surface thereof.

FIG. 3 is an enlarged front view of the electrode portion of the arc tube 1. The electrode coil 5 is held by two internal lead wires 6. An exhaust hole 8 is provided on one end side of the glass thin tube 7, and the other single side is sealed. An amalgam-forming substance 9 such as bismuth, indium, or lead is contained in one of the pair of glass capillaries 7.
A rod 10 is interposed between the exhaust hole 8 and the amalgam pellet 9 in order to prevent (hereinafter referred to as amalgam pellet) from dropping from the exhaust hole 8.

4 (a) to 4 (a) to FIG. 4 (a) to FIG.
This will be described below with reference to (c). FIG. 4A shows the first step in which the rod 10 and the cylindrical amalgam pellet 9 are inserted into the glass thin tube 7. FIG. 4 (b) shows the second step. In this step, in order to shorten the sealing portion of the glass thin tube 7 as much as possible, the heating burner (a portion near the upper end of the amalgam pellets 9) is used. The glass thin tube 7 is sealed by heating with (not shown). Therefore, in this step, the glass thin tube 7 is heated to a high temperature and the amalgam pellets 9 are also exposed to a high temperature. Figure 4 (c) shows the second
It shows a state in which the amalgam pellets 9 are enclosed in the glass thin tube 7 after the step (1).

Problems to be Solved by the Invention As described above, since it is necessary to make the glass capillary 7 as short as possible, the vicinity of the upper end of the amalgam pellet of the glass capillary 7 is heated. Therefore, the amalgam pellets 9 are always melted in the step of sealing the glass thin tube 7.

On the other hand, it is important to make the temperature distribution uniform in the cooling process after sealing the glass capillaries, especially in the vicinity of the strain point temperature of the glass capillaries. However, because of the above-mentioned configuration, the following problems occur. The contact portion of the amalgam pellets 9 of the glass capillaries 7 cools slowly, while the glass capillaries 7
The phenomenon that the non-contact portion (upper end portion in FIG. 4 (c)) of the amalgam pellet 9 is cooled faster occurs, and at the time of cooling at the strain point temperature, internal stress proportional to the temperature difference at that time is generated. As a result, there is a problem in that distortion remains in the glass capillaries, which causes cracks in the glass capillaries.

Means for Solving the Problems As a result of diligent research, the inventor found out that the cause of the above-described cracking of the glass thin tube was the residual strain of the sealed portion of the glass thin tube, and thoroughly investigated the solution. . Based on the results of the investigation, the present invention, in the step of enclosing the amalgam pellets in the glass capillary, the melting point of the amalgam pellets or higher, at a temperature lower than the strain point of the glass capillary, after melting the amalgam pellets inserted in the glass capillary. In this method, the glass thin tube is heated and sealed in the vicinity of the upper end of the amalgam pellet before being heated and melted.

Action In the step of melting the amalgam pellets inserted into the glass capillaries, even if there is a temperature difference between the glass capillaries and the amalgam pellets, the temperature of the glass capillaries is below the strain point, so no strain remains. Next, in the step of heat-sealing the glass thin tube, the amalgam pellets have already been melted and deformed, so that the temperature of the amalgam pellets becomes low as a result of the amalgam pellets moving away from the heat-sealing portion of the glass thin tube. There is. Therefore, in the cooling process after heating and sealing the glass capillaries, at the time when the temperature of the glass capillaries reaches the strain point temperature, the temperature distribution near the glass capillaries heating portion becomes uniform, and as a result, no strain remains in the glass capillaries.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1A to 1D are process drawings for explaining the method of the embodiment of the present invention.

Figure 1 (a) shows a strain point temperature of 315 ℃, inner diameter of 3.2mm, and length of about 100m.
2.8mm in outside diameter and length in the glass thin tube 7 made of lead glass of m
11 mm, rod body 10 made of lead glass of the same quality as the glass capillary,
And a bismuth with a melting point of 115 ° C, an outer diameter of 2.2 mm, and a length of 5 mm
Cylindrical amalgam pellets 9 made of indium alloy
The first step of inserting is shown.

FIG. 1B shows the second step, in which the glass capillary 7 is heated to about 150 ° C. by a heating burner (not shown).
Melt the amalgam pellets 9 in. As a result, the amalgam pellets 9 are transformed into elliptic spheres having a short diameter substantially equal to the inner diameter of the glass thin tube 7. At this time, since the maximum temperature of the glass thin tube 7 is 150 ° C., which is lower than the strain point temperature of the glass thin tube, no strain remains in the glass thin tube in the third step and the fourth step which will be described later. The means for melting the amalgam pellets 9 is not limited to the burner heating method.

FIG. 1 (c) shows the third step, in which the portion of the glass capillary 7 corresponding to the vicinity of the upper end of the amalgam pellet 9 in the original shape of the amalgam pellet 9 shown in FIG. 1 (a) is heated by a heating burner. It is a state diagram when it heats by (not shown).

FIG. 1D shows the fourth step, which is a state in which the amalgam pellets 9 are enclosed in the glass capillary 7.

In FIGS. 1 (a) to 1 (d), reference numeral 11 denotes a glass tube, the inner surface of which is coated with a phosphor (not shown).

In FIG. 1 (c), the amalgam pellets 9 are separated from the portion of the glass capillary 7 to be melted,
As a result of suppressing the temperature rise during the melting, the temperature of the glass in the vicinity of the contact portion of the glass thin tube 7 with the amalgam pellets 9 is lower than the strain point temperature, so that no strain remains. Further, when the glass thin tube 7 is sealed, the amalgam pellet 9 does not come close to the upper end portion of the glass thin tube 7 separated from the amalgam pellet 9, that is, the sealed portion of the glass thin tube 7 by a heating burner (not shown). The strain does not remain in the sealed portion, and the glass thin tube 7 is not cracked.

The effect of the present invention was confirmed by the following experimental data regarding the correlation between the residual strain of the glass capillary and the presence or absence of cracks in that portion.

That is, as a method for enclosing amalgam pellets, the conventional method shown in FIGS. 4 (a) to (c) and FIG. 1 (a) to
About the crack occurrence rate of the glass thin tube of the arc tube by the method of the present invention shown in (d), as a result of experimenting several times with 1000 pieces each, the crack occurrence rate in the case of the conventional method is 0.
While it was 1% to 0.6%, the crack occurrence rate in the case of the method of the present invention was 0%.

Effect of the Invention As described above, according to the present invention, in the step of sealing the glass thin tube having the amalgam pellets inserted therein,
Since no strain remains in the glass capillary, it is possible to provide a method for manufacturing a fluorescent lamp which can prevent cracks from occurring in the glass capillary.

[Brief description of drawings]

1 (a) to 1 (d) are process diagrams showing an embodiment of a method for manufacturing a fluorescent lamp of the present invention, FIG. 2 is a schematic diagram of a compact fluorescent lamp, and FIG. 3 is an enlarged front view of an electrode portion. FIG. 4 is a process drawing of a conventional fluorescent lamp manufacturing method. 7 …… Glass capillary, 9 …… Amalgam pellets, 10 ……
Stick body.

Claims (1)

[Claims] 1. An amalgam-forming substance inserted into a glass capillary is heated and melted at a temperature lower than the glass strain point of the glass capillary, and the glass capillary is heated and melted at the upper end of the amalgam-forming substance. A method of manufacturing a fluorescent lamp, characterized in that heat sealing is performed in the vicinity of the.