JPS6298531A - Manufacture of bent bulb type fluorescent lamp - Google Patents

Abstract

PURPOSE:To make it possible to form a large amount of a homogeneous smooth film on the inner surface of a glass tube by attaching a short glass tube having an inner diameter of 6-10mm and a length of 3-10mm to the curved section of a curved glass tube, applying a phosphor suspension to the inner surface of the glass tube and then introducing a gas into the glass tube through its openings. CONSTITUTION:After a hole 3 is formed in a U-shaped glass tube 2, a short glass tube 4 is fused to the hole 3 using a burner to produce a glass tube 5. The inner diameter of the tube 4 is 6-10mm and its length is within the range of 3-10mm. Then, phosphor suspension spray nozzles are inserted into the glass tube 5 through its openings 5A and 5B and a phosphor suspension is applied to the inner wall of the glass tube 5. Next, a drying gas is introduced into the glass tube 5 through the openings 5A and 5B and is discharged outside the glass tube 5 through the tube 4 after passing through the glass tube 5 in order to remove a surplus of the phosphor suspension within the glass tube 5 through the tube 4, thereby forming a dried phosphor film on the inner wall of the glass tube 5. After that, the glass tube 5 is baked and then the tube 4 is sealed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method of manufacturing a curved tube-shaped fluorescent lamp having a curved portion between openings at both ends.

2. Description of the Related Art In recent years, compact fluorescent lamps made of glass tubes formed into a U-shape or a roughly saddle shape have been put into practical use. As a method of manufacturing a fluorescent lamp having a plurality of curved portions of this type, the method described in Japanese Patent Laid-Open No. 134839/1983 is known. This method uses a glass tube having a plurality of curved parts, for example, roughly in the shape of a saddle, and among these curved parts, the curved parts located on the side of the openings at both ends of the glass tube are arranged along the opening direction of the openings at both ends. A phosphor suspension is then applied to the inner surface of the glass tube and dried. In this method, the excess phosphor suspension and drying gas are forcibly sucked out from the exhaust pipe to form a phosphor coating on the inner surface of the glass tube.

Problems to be Solved by the Invention However, in such a method, in the process of decomposing the binder contained in the phosphor suspension by firing, the inner diameter of the opening protrusion provided in the curved part is The supply of oxygen from the openings at both ends is greatly affected by the length, and it becomes difficult to completely decompose the binder in the curved portion. Therefore, the binder remains undecomposed, carbonizes, and remains in large amounts as carbon, which discolors the phosphor coating, which not only reduces the light output and increases the luminous flux maintenance rate during lamp operation, but also deteriorates the starting characteristics. It was recognized that such problems may occur.

On the other hand, when the excess phosphor suspension and drying gas are forcibly sucked from the curved exhaust pipe of the glass tube, it is necessary to precisely control the position of the exhaust pipe and the tip nozzle of the suction device. If the positioning is even slightly unregulated, the nozzle may hit the exhaust pipe and break, or the nozzle may become clogged due to dripping of the phosphor suspension, making it impossible to suck in the drying gas, resulting in deterioration of the film surface.

In addition, there were many other problems, such as splashes of the fluorescent suspension on the suction device, which could cause the device to malfunction, and require a lot of time for maintenance, making it unsuitable for mass production.

The present invention was made to eliminate such problems, and the binder contained in the phosphor suspension can be sufficiently decomposed by baking, and the phosphor coating can be coated on the inner surface of the glass tube. The purpose of the present invention is to provide a method for manufacturing a curved tube type fluorescent lamp, which can homogeneously and stably produce a large amount of curved fluorescent lamps.

Means for Solving the Problems The present invention provides a glass tube having an inner diameter of 6 to 10 mm and a length of 3 mm so as to be located at the center of the curved head of a glass tube having a curved section between both openings.
After providing ~10 opening protrusions and applying a phosphor suspension containing a binder to the inner surface of the glass tube, gas is introduced into the glass tube from the openings at both ends, and the inside of the glass tube is heated. A phosphor coating is formed on the inner surface of the glass tube by drying the phosphor suspension applied to the surface.

Function: With this configuration, in the process of decomposing the binder contained in the phosphor suspension by firing, it is possible to remove the binder from the openings at both ends only by the inner diameter and length within a specific range of the opening convex part. Enough oxygen can be supplied, luminous flux, luminous flux maintenance rate,
Starting characteristics etc. will be improved. Furthermore, after applying the phosphor suspension to the inner surface of the glass tube, the phosphor suspension does not accumulate in the curved part and form a thick film, and excess phosphor suspension does not leak out from the opening convex part. Since there is no need to forcibly suck the drying gas, problems such as defect rate, failure rate, maintenance, etc. due to the precision of regulating the position of the opening protrusion and the suction device can be solved.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

First, as shown in FIG.
The U-shaped glass tube 2 having the shape shown in FIG. 3 is formed by heating and softening the tube and rotating the one end A and the other end B in a direction toward each other.

Next, one end A is sealed, and a small amount of air is introduced from the other end B. At the same time, the center of the head of the bent part of the U-shaped glass tube 2 is heated and softened with a burner (not shown) to open the hole 3. After opening, the opening convex portion 4 is fused to that portion using a burner (not shown), thereby obtaining a glass tube 5 having the shape shown in FIG. 1. The opening convex portion 4 has an inner diameter of 6 to 10 mm and a length of 3 to 10 mm.
- is used.

Next, the glass tube 5 is held and fixed vertically with a holder (not shown) so that the openings 5A and 5B at both ends are located on the upper side, and the phosphor suspension injection nozzle is inserted from the openings 5A and 5B at both ends. After inserting and applying the phosphor suspension to the inner surface of the glass tube 5,
When the drying gas is introduced from the openings 5A and 5B at both ends of the glass tube 6, the drying gas passes through the glass tube 5 and is released from the opening protrusion 4 to the outside. Excess phosphor suspension is discharged from the opening protrusion 4. By drying in this manner, a phosphor coating is formed on the inner surface of the glass tube 5. Next, after the glass tube 5 is baked, the opening protrusion 4 is sealed and a predetermined process is completed to complete the lamp.

According to the method described above, the excess phosphor suspension injected into the curved glass tube does not accumulate on a specific part and become a thick film, which prevents it from forming a thick film. A stable, smooth and homogeneous phosphor coating can be obtained on the inner surface. Next, we varied the inner diameter and length of the convex opening of the glass tube and used these to investigate the state of sintering decomposition of the binder contained in the phosphor suspension. The results are as shown in Table 1. As shown in Table 1, if the inner diameter of the convex opening of the glass tube 5 is 5 mm or less, the decomposition of the binder will not occur even if the length is changed. Enough and the amount of carbon is 0. Q3 - 0.04% (same as the conventional method using a glass tube without openings and protrusions).

On the other hand, if the inner diameter of the opening convex part is 11 mm or more, the decomposition of the binder is almost sufficient even if the length is slightly changed, and the carbon content is a slightly satisfactory value of 0.01 to 0.02%. However, it becomes difficult to seal after firing and to weld and join the opening convex portion to the curved portion 3 of the glass tube 2.

It should be noted that if the length of the opening protrusion is shorter than 3-fold, it becomes difficult to seal after firing and to weld and join the opening protrusion to the curved part 3 of the glass tube 2.

Next, an 18-watt curved tube fluorescent lamp was manufactured using glass tubes with lengths of 3, 6, 10, and 11.16 mm by changing the inner diameter of the convex opening of the glass tube in a range of 3 to 15 mm. When the total luminous flux and the luminous flux maintenance rate after 2000 hours were measured for each lamp, the results shown in Table 2 were obtained.

Table 2 As is clear from Table 2, in the curved tube fluorescent lamp obtained by the method of the present invention, there is no significant improvement in total luminous flux compared to the conventional example, but after lighting for 20 oO hours, The luminous flux maintenance rate is 87 to 96% when the inner diameter of the aperture convex part is 6 mm or more.
It can be seen that this is a significant improvement compared to 84% of the conventional example.

However, as described above, if the inner diameter of the opening protrusion exceeds 10 gates, it becomes difficult to seal after firing and to weld and join the opening protrusion to the curved part 3 of the glass tube 2.

Therefore, from Tables 1 and 2, the inner diameter of the opening protrusion is 6.
By using a curved glass tube having a length of 3 to 10 mm and a length of 3 to 10 mm, the total luminous flux and luminous flux maintenance factor could be sufficiently satisfied.

Furthermore, according to the method of the present invention, when applying and drying the phosphor suspension on the inner surface of the glass tube 5, as long as the inner diameter of the aperture convex portion 4 is 6 mm or less, there will be no surplus regardless of the length. If the phosphor suspension and the drying gas are not forcibly sucked as in the conventional method, the phosphor suspension will accumulate in the opening protrusion 4, so the drying gas is drawn into the glass tube 6A. Even if it is introduced from 6B, the tube will be filled, and the drying speed of the phosphor suspension coated on the inner surface of the glass tube 6 will be extremely slow, damaging the film surface. Furthermore, if the inner diameter of the aperture protrusion 4 is 6 or more and the length is 11 or more, the aperture protrusion 4 may become clogged even if excess phosphor suspension and drying gas are not forcibly sucked. However, it becomes difficult to seal the opening protrusion 4 after baking after coating and to weld and join the opening protrusion to the curved part 3 of the glass tube 2.

From the above, the method of the present invention, that is, if the inner diameter of the opening protrusion 4 is within the range of 6 to 10 mm and the length is within the range of 3 to 10 mm,
When applying and influencing the inner surface of the glass tube 5 with the phosphor suspension, there is no need to forcibly suck the opening convex portion 4.
It was found that a stable, smooth and homogeneous film could be obtained without any problems, and that it was suitable for mass production.

Note that the method of the present invention can be similarly implemented for glass tubes having not only one bending section but also a plurality of bending sections (for example, a saddle shape).

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention provides a curved portion of a glass tube having an inner diameter of 6 to 10 mm and a length of 3 to 3 mm.
A phosphor coating is applied to the inner surface of the glass tube by providing a convex opening between 10 and 10 mm, applying a phosphor suspension to the inner surface of the glass tube, and then introducing gas into the glass tube from the openings at both ends. can be uniformly and smoothly formed in large quantities, and the decomposition of the binder contained in the phosphor suspension can be improved in the firing process. As a result, not only the power distribution of the lamp becomes uniform, but also the light output and the luminous flux maintenance rate can be greatly improved, which is an excellent effect suitable for mass production.

[Brief explanation of drawings]

FIGS. 1 to 3 are process explanatory diagrams of an embodiment of the method of the present invention. 1.2.5...Glass tube, 4...Opening convex part, 6...Glass tube bending part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4 - View u6 elevation 5''-° Re-lased tube 6- ・Kurakuiri Shinyu 3 Figure

Claims (1)

[Claims] A glass tube with an inner diameter of 6 to 10 mm and a length of 3 to 10 m so as to be located in the center of the curved head of a glass tube having a curved part between openings at both ends.
After applying a phosphor suspension containing a binder to the inner surface of the glass tube, a gas is introduced into the glass tube from the openings at both ends, and the inside of the glass tube is heated. A method for manufacturing a curved tube fluorescent lamp, characterized in that a phosphor coating is formed on the inner surface of the glass tube by drying a phosphor suspension applied to the surface.