JP2001357782A - Fabrication process of fluorescent lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fabrication process of a fluorescent lamp, by which even curved surface and uniform thickness distribution can be achieved at the seated ends to improve strength. SOLUTION: After nearly the central part 10 of a glass tube 1 is heated, proper heating is conducted. By this heating, the central part 10 is gradually softened to become narrower in diameter, and is finally closed while the remaining unseparated. In this closed state, gas is blown in from both open ends of the glass tube 1 to form inner closed ends 7a, 7b into curved surfaces. While the gas is kept on blowing, the glass tube 1 is fused to form glass tubes 8a, 8b. Outer closed ends 9a, 9b of the glass tubes 8a, 8b are successively heated to arrange the shapes thereof, and the glass tubes are then transferred to an annealing step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fluorescent lamp having an arc tube connected to a glass tube such as a bulb-type fluorescent lamp and a compact fluorescent lamp.

[0002]

2. Description of the Related Art Conventionally, as a light emitting tube of a fluorescent lamp, two straight tubular glass tubes having a closed portion at one end and an opening at the other end are bridge-connected in the vicinity of the closed portion to form one light emitting tube. Tubes are known.

The following two methods are known as a method of manufacturing such an arc tube, particularly, a method of manufacturing a glass tube before connection by bridge connection or the like.

A first method is disclosed in Japanese Patent Publication No. 4-58.
As shown in Japanese Patent Application Publication No. 137, after heating the area near the center of the glass tube at both ends and closing it, fusing the area near the center and dividing the glass tube, the closed part is straightened in the glass axis direction in the tube axis direction. A method of manufacturing a glass tube is known in which a flat member is shaped by blowing gas from an open end while applying an abutting member to the end surface of the closing portion from outside the closing portion so as to form an end surface perpendicular to the portion. . The second method is disclosed in
As shown in Japanese Patent Application Laid-Open No. -40057, after a glass tube having one open end is heated and softened, and further heated and continued to be blown and divided, the closed portion formed by this division is in a softened state. In the meantime, there is known a method of manufacturing a glass tube in which a gas is blown into the glass tube so that the closed portion has a convex curved shape.

[0005]

However, since the fluorescent lamps manufactured by the above-described conventional methods are blown with gas after being divided, the fluorescent lamps have uneven thickness portions on the curved and flat surfaces of the closed end faces, It was confirmed that distortion was slightly generated.

The present invention provides a method of manufacturing a fluorescent lamp capable of obtaining a more uniform curved surface and a uniform thickness distribution as compared with the prior art in the thickness of the closed end face and improving the strength at the closed portion. The purpose is to gain.

[0007]

According to a method of manufacturing a fluorescent lamp according to the present invention, an area to be divided of one glass tube to be divided is heated, softened and closed, and the area to be divided is blown to one end. Are formed to form two closed glass tubes, and when the predetermined area to be divided is blown, the shape of the closed part is changed during a period from the state in which the predetermined glass tube to be divided is softened and closed to the time of division. Is a hemispherical shape, and so that the outer closed end face and the inner closed end face of the closed portion and the straight portion of the glass tube are not at a right angle,
It is configured to start blowing gas from the openings at both ends of the glass tube to be divided.

According to the present invention, the gas is started to be blown from the openings at both ends during the period from the state in which the planned division region of the glass tube to be divided is being closed to the time when the glass tube is to be divided. It is possible to perform curved surface shaping on the closed portion from the front. Then, when divided by fusing, the outer closed end surface (outer surface) and the inner closed end surface (inner surface) of the closed portion are curved, so that a substantially uniform curved shape can be formed on the outer closed end surface and the inner closed end surface of the closed portion. At the same time, it is possible to prevent variations in wall thickness and distortion of the closed portion.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a fluorescent lamp according to an embodiment of the present invention will be described with reference to the drawings.

As will be described later, the fluorescent lamp 14 shown in FIG.
Is manufactured as shown in FIG. That is, while rotating one glass tube 1 to be divided made of soda glass or the like having openings at both ends, a substantially central portion 10 which is a region to be divided of the glass tube 1 has a plurality of flame outlets. Heating is performed by the preheating gas burner 2 (FIG. 1A). Thereafter, the preheated substantially central portion 10 of the glass tube 1 is fully heated by the main heating gas burner 3. Due to this main heating, the central portion 10 gradually softens and becomes smaller in diameter (FIG. 1 (B)), and is finally closed while being connected to form the closed portion 6. Then, when the glass tube 1 is closed while being connected, gas such as air or an inert gas is simultaneously blown from both ends of the glass tube 1 to form the inner closed end surfaces 7a and 7b into curved surfaces (FIG. 1).
(C)). Next, the glass tube 1 is blown by the point burner 4 at the closing portion 6 of the area to be divided while the gas is being blown, and divided into two to form the divided glass tubes 8a and 8b (FIG. 1D). And the divided glass tube 8
Subsequently, the outer closed end faces 9a, 9b of a, 8b are continuously heated by the point burner 4, and after undergoing a shaping step (FIG. 1 (E)) for finishing a smooth curved surface, distortion is removed by the annealing gas burner 5. (FIG. 1F). In the above description, gas blowing is started when the glass tube 1 is closed while being connected (see FIG. 1 (C)). However, when the glass tube 1 is softened and closed. Gas blowing may be started (see FIG. 1B).

The gas blown from the openings of the glass tubes 8a and 8b is stopped before the gas is transferred to the annealing step, and the pressure of the gas at each stage is controlled by the inner closed end face 7a. , 7b and outer closed end faces 9a, 9b
Are selected to such a level that no irregularities or variations in the glass thickness occur on the curved surface. Further, the gas may be intermittently or continuously supplied.

FIG. 2 shows a glass tube 8 obtained by the method of manufacturing a fluorescent lamp according to one embodiment of the present invention.
a, 8b. That is, the divided glass tubes 8a and 8b are integrated with each other by bridging the vicinity of the closed portion at one end by the connecting portion 11 and providing electrodes (not shown) at the openings at the other end. Thus, an arc tube 12 having one discharge path formed between the electrodes is formed. The end of the arc tube 12 provided with the electrode is fixed to the base 13, and the fluorescent lamp 14 is finally completed. Note that a fluorescent material (not shown) is attached to the inner surface of the fluorescent lamp 14.

An embodiment of the present invention will be described below.

Total length 340 mm, glass tube outer diameter 20 m
As shown in FIG. 2, a compact fluorescent lamp FPL28 (28W) having two tubes was manufactured.

A normal three-wavelength light emitting region type rare earth phosphor is applied to a straight glass tube 1 to be divided, which is made of soda glass having an outer diameter of 20 mm and a thickness of 1 mm, and has openings at both ends of 700 mm in length. After baking, from the start of preheating to the end of annealing, they are placed on all 19 transfer rollers and transferred by rotation. During this transfer, various burners are installed as shown in FIG. Preheating gas burner 2 has a hole diameter of 1m
5 nozzles at 5 mm intervals in two rows, with the longer side of the gas burner positioned parallel to the axis of the glass tube, and the substantially central portion
The preheating (FIG. 1A) is performed with the width of 0 being about 4 cm. The section from the first roller provided with the preheating gas burner 2 to three rollers is a preheating section. Next, the main heating gas burner provided with one row of five nozzles is arranged such that the longer burner surface is orthogonal to the axis of the glass tube 1 and the main heating (FIG. 1B) and the closing (FIG. 1B). 1
(C)), fusing (FIG. 1 (D)), and shaping of the outer closed end surface (FIG. 1 (E)). In each of the above steps, main heating is performed in a section of four rollers, blockage is performed in a section of three rollers, fusing is performed in a section of two rollers, and shaping is performed in a section of three rollers. The area to be divided of the glass tube 1 is softened and reduced in diameter by being heated, and finally closed while being connected. In the closed state, the shaping gas is simultaneously supplied from the openings at both ends of the glass tube 1 to form the closed portion 6 into a curved surface, which is melted and divided. Then, the outer closed end faces 9a, 9b of the divided glass tubes 8a, 8b are shaped, and finally, a plurality of nozzles are arranged by an annealing gas burner arranged in parallel with the tube axes of the divided glass tubes 8a, 8b. Anneal in the section of four rollers (Fig. 1 (F))
Then, the slow cooling was completed.

The glass tubes 8a, 8 thus obtained
b were connected using a conventional bridging means to form an arc tube 12, and a fluorescent lamp 14 was produced as shown in FIG.

The closed end faces on the outer and inner sides of the glass tubes 8a and 8b obtained by such a process have a substantially hemispherical curved surface and are as thick as 0.9 to 1.1 mm.
It has a uniform thickness.

Next, 100 fluorescent lamps of the present embodiment (hereinafter, referred to as the present invention) and 100 comparative products described below were manufactured, and the strength and thickness of the closed portion were measured.

As comparative products, a fluorescent lamp (hereinafter referred to as comparative product A) manufactured by using the manufacturing method described in Japanese Patent Application Laid-Open No. 4-58137 shown in the above-mentioned prior art, and Japanese Patent Application Laid-Open No. 11-40057 A fluorescent lamp manufactured by using the manufacturing method described in Japanese Patent Application Laid-Open Publication No. H10-209 (hereinafter referred to as comparative product B) was used.

The strength test for the product of the present invention, the comparative product A, and the comparative product B was performed according to JEL601 (19)
The test was carried out based on the December 6, 1996 edition "General rules for the safety test of light source products".

First, regarding the strength of the closed portion of the glass tube,
A test was conducted in which a steel ball weighing 4 g was dropped from a height of 15 cm onto the closed part of the glass tube.

As a result, the product of the present invention is damaged, abnormally distorted,
There was no occurrence of cracks or the like in 100 pieces. On the other hand, as for the comparative product A, three pieces were found to be damaged and five pieces were found to have cracks. Also, in the comparative product B, slight abnormal distortion was confirmed for two pieces.

Further, as a packaging drop test, 20 boxes each containing 50 fluorescent lamps were prepared, and the conditions of the above JEL601 were made slightly strict, and from a height of 65 cm, one corner, two ridges, and three faces were prepared. Then, a drop test on a concrete surface was performed once.

As a result, no crack or abnormal distortion was observed in the product of the present invention. On the other hand, it was confirmed that the comparative product A had 16% of defects such as cracks, abnormal distortion, and breakage, and the comparative product B had 4% of defects.

From the above measurements, it was confirmed that the product of the present invention is superior in strength at the closed portions of the glass tubes 8a and 8b as compared with the comparative products A and B.

Next, with respect to the product of the present invention, the comparative product A and the comparative product B, the shape and thickness distribution of the closed portion of the glass tube were confirmed.

As a result, the thickness of the closed portion is less than 0.8 times the thickness of the straight portion of the glass tube compared with the straight portion of the glass tube. It had a shape that easily caused distortion and cracks.

Further, the comparative product B has a spherical surface similar to the closed portion of the product of the present invention in the shape of the closed portion, but the outer closed surface and the inner closed surface each show slight variations in shape. The thickness distribution was not always uniform as compared with the product of the present invention.

For this reason, in the comparative product A and the comparative product B, when subjected to a thermal shock or a physical shock, there is a possibility that a problem in terms of strength, such as abnormal strain, may occur.

On the other hand, the product of the present invention has better spherical curved surfaces on both the outer and inner closed end faces and the uniform wall thickness distribution as compared with the comparative product A and the comparative product B. There was also an improvement in strength. Further, the wall thickness of the closed portion with respect to the straight portion of the glass tube exceeded 0.8 times, so that safety could be sufficiently maintained.

[0031]

As described above, the method for manufacturing a fluorescent lamp according to the present invention increases the productivity of a fluorescent lamp having an arc tube connected to a glass tube, and reduces the shape and thickness of the closed portion of the glass tube. It can be formed more stably than before, and the strength can be improved. For this reason, the fluorescent lamp manufacturing process, transport process, packing process, transfer after packing, mounting on equipment, lighting, etc. It is possible to prevent breakage due to thermal shock or physical shock during proper use, improve safety, and stabilize quality and improve productivity.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a method of manufacturing a fluorescent lamp according to an embodiment of the present invention.

FIG. 2 is a partially cutaway front view of a fluorescent lamp according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Divided glass tube 2 Preheating gas burner 3 Main heating gas burner 4 Point burner 5 Annealing gas burner 6 Closed part 7a, 7b Inner closed end face 8a, 8b Split glass tube 9a, 9b Outer closed end face 10 Central part 12 Light emission tube

Continued on the front page (72) Inventor Toshitaka Ogasawara 1-1, Sachimachi, Takatsuki-shi, Osaka, Japan Inside Matsushita Electronics Corporation (72) Inventor Kiyoshi, 1-1 1-1 Sachimachi, Takatsuki-shi, Osaka, Matsushita Electronics Corporation F term (reference) 5C012 AA08 EE03 EE10

Claims (1)

[Claims] An object of the invention is to heat, soften, and close a scheduled dividing region of one scheduled dividing glass tube, and to blow off the scheduled dividing region to form two glass tubes having one end closed. When fusing the planned dividing area,
Between the state in which the glass tube to be divided is softened and closed and the state in which the glass tube is divided, the shape of the closed portion is a hemispherical shape, and the outside closed end surface and the inside closed end surface of the closed portion, and the straight line of the glass tube A method for manufacturing a fluorescent lamp, characterized in that gas is started to be blown from openings at both ends of the glass tube to be divided so that the portions do not form a right angle.