JPH06150825A - Manufacture of high pressure electric discharge lamp light emitting tube - Google Patents

Abstract

PURPOSE:To provide a light emitting tube for a high pressure electric discharge lamp having a long lifetime at a low cost without a danger of bursting by increasing pressure withstand strength of the light emitting tube in a simple process. CONSTITUTION:Electrodes 2, 3 are air-tightly sealed in a light emitting tube 1 of a high pressure electric discharge lamp via metal dies 6, 7, and then, a range from the boundary between the light emitting portion and sealing portion of the light emitting tube to the center of a metal foil conductor is heated by an oxygen/hydrogen burners 4, 5. Partly pressing by means of metal dies 6a, 7a can realize a low cost and a long lifetime.

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 high pressure discharge lamp arc tube having at least one pinch seal portion, which is applied to a metal halide lamp or the like.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for using high-pressure discharge lamps not only for wide area lighting such as roads, plazas, and stadiums, but also for indoor lighting such as stores. In particular, metal halide lamps are widely used as light sources for overhead projectors, overhead type liquid crystal projection televisions, projectors, etc., in addition to lighting for display products, because of their high color rendering properties and high efficiency.

An example of the above-described arc tube of the conventional high pressure discharge lamp and a manufacturing process thereof will be described below with reference to the drawings. In FIG. 2, reference numeral 8 denotes an arc tube light emitting portion formed of quartz glass and having an elliptical shape, and a pair of electrode shafts 9 and 10 are sealed at both ends. Arc tube sealing part 1
1 and 12 are metal foil conductors 13 and 14 made of molybdenum
Are sealed, and the electrode shafts 9 and 10 are connected to the metal foil conductors 13 and 14, respectively. And
External lead wires 15 and 16 are connected to the other ends of the metal foil conductors 13 and 14, respectively. An exhaust thin tube 17 for enclosing the additive is attached to the center of the light emitting portion of the arc tube. After sealing the additives, this exhaust thin tube 1
7 is melted with a burner or the like and separated to form a light emitting tube.

Now, a conventional manufacturing process for hermetically sealing the electrodes will be described. In FIG. 3, 18 to 23 are burners,
24 and 25 are molds, 26 is an electrode, and 27 is a quartz glass arc tube. The electrode 26 is set in the quartz glass tube 27, and the quartz glass is melted by the oxygen / hydrogen burners 18 to 23 while flowing an inert gas in the quartz glass tube, and then pressed by the molds 24 and 25 to hermetically seal. Has been used.

[0005]

However, the vapor pressure in the arc tube is high when the high-pressure discharge lamp is lit, for example, the vapor pressure of a small metal halide lamp is 20 to 40 atm, and when the arc length is shorter than the conventional one, it is 50 atm. It is very high up to -100 atm, and in the above-mentioned manufacturing method, since the hermetic sealing is insufficient, the arc tube pressure resistance is weak and there is a risk of bursting. Further, in the case of hermetically sealing the electrodes, the manufacturing cost becomes extremely high in the method by manual processing called hand-sealing.

In view of the above problems, the present invention provides a method for manufacturing an arc tube for a high pressure discharge lamp which can increase the pressure resistance of the arc tube in a simple process, has a low risk of bursting, and has a long life. With the goal.

[0007]

In order to solve the above-mentioned problems, a method of manufacturing a high pressure discharge lamp arc tube according to the present invention comprises at least one electrode hermetically sealed, and then at least the arc tube light emitting section of the sealing section. The step of reheating the electrode shaft to the metal foil conductor joint portion from the boundary of the arc tube sealing portion and pressing with a die is provided.

[0008]

With the above-described structure, the present invention makes it possible to manufacture a high-pressure discharge lamp having a high arc tube strength by a simple process as compared with a conventional high-pressure discharge lamp, so that it is inexpensive and has a long life.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a manufacturing process diagram for explaining a method of manufacturing a high pressure discharge lamp arc tube according to an embodiment of the present invention.
First, the electrodes 2 and 3 are attached to the arc tube 1 of the high pressure discharge lamp by the conventional method.
Is hermetically sealed. After that, using the same device, the oxygen-hydrogen burners 4 and 5 are used again to heat the boundary between the arc tube light emitting part and the arc tube sealing part to the central part of the metal foil conductor to about 2000 ° C.,
Partial press with dies 6 and 7. As shown in FIG. 1, in order to perform the step of hermetically sealing and the step of partially pressing from the boundary between the arc tube light emitting part and the arc tube sealing part to the central part of the metal foil conductor, the molds 6, 7 are used. Are composed of a and b. When airtightly sealed, two of 6a, 7a and 6b, 7b are operated at the same time, and when partially pressed, a metal is drawn from the boundary between the arc tube light emitting part and the arc tube sealing part. Only the molds 6a and 7a up to the center of the foil conductor are operated and pressed.

After air-tightly sealing the electrodes in this way, at least the arc tube light emitting section of the sealing section and the boundary between the arc tube sealing section and the electrode shaft and the metal foil conductor joint section are heated again, and then the section is formed by the die. A pressure resistance test and a life test performed to compare the pressure resistance of the pressed arc tube and the conventional arc tube will be described. The pressure resistance test is a test in which nitrogen is flown into the arc tube and the pressure at the time of bursting is measured. In the life test, the high-pressure discharge lamp was turned on for 5.5 hours and turned off for 0.5 hours, and the cumulative amount of lighting time when the lamp exploded was shown. The results are shown in (Table 1).

[0011]

[Table 1]

As can be seen from (Table 1), after sealing the electrodes in an airtight manner and heating at least the arc tube light emitting section and the arc tube sealing section boundary from the sealing section to the electrode shaft and the metal foil conductor joint section again, When the arc tube partially pressed by the mold was used, extremely excellent characteristics were obtained.

The present invention is not limited to the manufacturing method described in the above embodiment, but may be heated by laser or high frequency heating instead of the burner. Further, the device for hermetically sealing the electrodes and the device for partial pressing may be different. Further, in the description of the above embodiment, the step of reheating and pressing after airtightly sealing is one time, but it may be performed a plurality of times.

[0014]

As described above, according to the present invention, after hermetically sealing the electrodes, at least the arc tube light emitting section and the arc tube sealing section boundary of the sealing section to the electrode shaft and the metal foil conductor joint section are sealed. By providing a simple process of heating again and pressing with a die, it is possible to achieve a lower cost and a longer life as compared with a conventional high pressure discharge lamp arc tube.

[Brief description of drawings]

FIG. 1 is a process diagram illustrating a method of manufacturing a high pressure discharge lamp arc tube according to an embodiment of the present invention.

FIG. 2 is a front view of a high pressure discharge lamp arc tube.

FIG. 3 is a process diagram illustrating a method of manufacturing a conventional high pressure discharge lamp arc tube.

[Explanation of symbols]

 1 arc tube 2,3,9,10 electrode shaft 4,5 burner 6,7 mold 8 arc tube light emitting part 11,12 arc tube sealing part 13,14 metal foil conductor 15,16 external lead wire 17 exhaust thin tube

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hideto, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inoue, Munehiro Tabata 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd

Claims (1)

[Claims] 1. A method of manufacturing a high-pressure discharge lamp arc tube comprising an arc tube having a pair of sealed electrodes, wherein at least one of the electrodes is hermetically sealed, and then at least the arc tube light emission of the sealing part is performed. A method for manufacturing a high pressure discharge lamp arc tube, comprising heating again from the boundary between the arc tube and the arc tube sealing section to the electrode shaft-metal foil conductor joint section and pressing with a mold.