JPH07176296A - Seal method for metal vapor discharge tube - Google Patents

Abstract

PURPOSE:To prevent metal vapor from leaking in the case of sealing a metal vapor electric discharge lamp tube. CONSTITUTION:A metal seal object 10 of metal halide, amalgam, etc., is charged through a platinum pipe 5 secured to an opening 3 of a discharge tube 1. Next, a platinum cap 12, provided with a tungsten electrode 11, is inserted into the platinum pipe 5 secured to the opening 3, and a low melting point metal brazing 13 is set between this platinum cap 12 and the platinum pipe 5. By heating this part by a high frequency or the like, a clearance between the platinum cap 12 and the platinum pipe 5 is sealed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of sealing an arc tube end of a metal vapor discharge lamp such as a metal halide lamp or a sodium lamp.

[0002]

2. Description of the Related Art A metal vapor discharge lamp such as a metal halide lamp or a sodium lamp has a transparent arc tube in which a metal halide or amalgam is enclosed, and a high voltage is applied between the internal electrodes inserted in the arc tube so that a high voltage is applied between the electrodes. An arc discharge is generated, and the metal halide enclosed in the arc tube is evaporated by the heat generated by the arc discharge, dissociated into a metal and a halogen, and light emission exhibiting a color peculiar to the metal is performed.

In order to encapsulate the above-mentioned metal enclosure such as metal halide or amalgam in the arc tube, a cap provided with an electrode is inserted into one end opening of the arc tube, and the outside of this insertion part is sealed with glass solder. Then, a metal halide or the like is put into the arc tube through the opening at the other end, and then a cap provided with an electrode is inserted at the opening at the other end to seal the outside with glass solder.

[0004]

In the above-mentioned method for sealing an arc tube, the other end opening is sealed after a metal halide or the like is put into the arc tube. The glass solder used for this sealing is used. Has a high melting point (1450 to 1550 ° C)
Therefore, the metal halide and the like put into the arc tube evaporates and leaks due to the heat when the other end opening is sealed. In particular, when the arc tube is downsized, the above-mentioned disadvantage becomes remarkable because the distance between the portion to which heat is applied and the metal halide or the like becomes short, and therefore the size of the arc tube cannot be reduced, and the low It is difficult to make watts (power saving).

[0005]

In order to solve the above-mentioned problems, the first invention of the present application is such that at least one of the openings formed at both ends of the arc tube, which is to be sealed later, is provided with a metal tube in advance on the inner surface of the opening. It is fixed so that it is airtight between the outer surface of the metal pipe, and after inserting the cap into this fixed metal pipe,
The metal tube and the cap were sealed by heating the part away from the opening.

According to the second invention of the present application, of the openings formed at both ends of the arc tube, the openings to be sealed first are sealed with a high melting point glass solder, and the openings to be sealed later are low. The cap was sealed with a melting point metal solder.

[0007]

In the first aspect of the invention, the metal encapsulation contained in the arc tube is devised by devising the heating position at the time of sealing, and in the second aspect of the invention, by using the sealing agents having different melting points. Prevents an object from evaporating and leaking during sealing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the first invention of the present application will be described below with reference to FIGS. Here, as an embodiment of the first invention, openings 2 and 3 are formed at both ends of a translucent arc tube 1 made of Al ₂ O ₃ , and platinum pipes 4 and 5 are half of the openings 2 and 3, respectively. Then, the inner surfaces of the openings 2 and 3 and the outer surfaces of the platinum pipes 4 and 5 are hermetically sealed by the glass solder 6.

In the first aspect of the invention, first, as shown in FIG. 1, a platinum cap 8 having a tungsten electrode 7 is inserted into a platinum pipe 4 fixed to an opening 2 at one end of an arc tube 1, The platinum cap 8 and the outer ends of the platinum pipe 4 are sealed with a brazing metal 9 having a relatively low melting point.

After that, a metal enclosure 10 such as a metal halide or amalgam is put into the arc tube 1 through a platinum pipe 5 fixed to the opening 3 at the other end, and then the other end as shown in FIG. The platinum cap 12 provided with the tungsten electrode 11 is inserted into the platinum pipe 5 fixed to the opening 3 of the above, a low melting point metal braze 13 is set between the platinum cap 12 and the platinum pipe 5, and this portion is subjected to high frequency wave or the like. The gap between the platinum cap 12 and the platinum pipe 5 is sealed by heating with, and the openings 2 and 3 at both ends as shown in FIG.
The arc tube 1 which is sealed with 12 and in which the metal enclosure 10 is enclosed is obtained.

In the above embodiment, a metal brazing material having a low melting point is used to seal the platinum cap and the platinum pipe.
Although the leak of the metal enclosure is surely prevented, in the first invention, since the heating portion at the time of sealing is separated from the metal enclosure inside the arc tube, a high melting point glass solder may be used. . Further, in the above-mentioned embodiment, the structure in which the platinum pipes are fixed to the openings of both ends of the arc tube is shown. However, the one end opening of the arc tube (the opening which is sealed first) is made of an ordinary ceramic. The cap may be used for sealing.

Next, an embodiment of the second invention of the present application will be described with reference to FIGS. 4 and 5. In the second aspect of the invention, first, referring to FIG.
As shown in, a niobium tube 24 having a tungsten electrode 23 is inserted into the opening 22 at one end of the arc tube 21, and the outside of the inserted portion is sealed with a high melting point glass solder 25,
Then, a metal enclosure 27 such as a metal halide or amalgam is put into the arc tube 21 through the opening 26 at the other end.

Next, as shown in FIG. 5, the opening 26 at the other end is formed.
A niobium tube 29 equipped with a tungsten electrode 28 is inserted in and the outside of the inserted portion is sealed with a low melting point metal braze 30. By thus sealing with the metal melting point 30 having a low melting point, the time required for sealing can be shortened and the evaporation of the metal enclosure 27 in the arc tube 21 can be suppressed.

[0014]

As described above, according to the first invention of the present application, the metal tube is preliminarily provided in at least one of the openings formed at both ends of the arc tube which is sealed from the inside and outside of the metal tube. It is fixed so that it is airtight between the side surface, and after inserting the cap into this fixed metal tube, the metal tube and the cap are sealed by heating the part away from the opening. Further, it is possible to suppress evaporation and leakage of the metal enclosure placed in the arc tube due to heat at the time of sealing, it is possible to reduce the size of the arc tube itself, and it is possible to save power.

According to the second invention of the present application, of the openings formed at both ends of the arc tube, the opening to be sealed first is sealed with a high melting point glass solder, and the opening to be sealed later. Since the cap is sealed with the low melting point metal solder, the leakage of the metal inclusion can be suppressed as in the first aspect of the invention, and the arc tube itself can be downsized and the power consumption can be saved.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which one end opening of an arc tube is sealed in a sealing method according to a first invention.

FIG. 2 is a view showing a state before sealing the other end opening of the arc tube in the sealing method according to the first invention.

FIG. 3 is a view showing an arc tube sealed by the sealing method according to the first invention.

FIG. 4 is a view showing a state in which one end opening of the arc tube is sealed in the sealing method according to the second invention.

FIG. 5 is a diagram showing an arc tube sealed by a sealing method according to a second invention.

[Explanation of symbols]

1, 21 ... Arc tube, 2, 22 ... One end opening of arc tube, 3,
26 ... Opening of other end of arc tube, 4, 5 ... Platinum pipe, 6, 2
5 ... High melting point glass solder, 8, 12 ... Platinum cap,
9,13,30 ... Low melting metal braze, 10,27 ... Metal enclosure.

Claims (2)

[Claims] 1. A metal vapor arc tube in which one end opening of the arc tube is sealed with a cap, a metal enclosure is introduced into the arc tube through the other end opening, and then the other end opening is sealed with a cap. In the sealing method described above, a metal tube is fixed in advance to at least the opening to be sealed later so that the inner surface of the opening and the outer surface of the metal tube are hermetically sealed, and a cap is placed in the metal tube. After the insertion, the metal tube and the cap are sealed by heating at a position apart from the opening, wherein the metal vapor arc tube is sealed. 2. A metal vapor arc tube in which one end opening of the arc tube is sealed with a cap, a metal enclosure is introduced into the arc tube from the other end opening, and then the other end opening is sealed with a cap. In the sealing method, the opening to be sealed first is a cap with a high melting point glass solder, and the opening to be sealed later is a cap with a low melting point metal solder. A method for sealing a metal vapor arc tube, comprising: