JPS6290828A - Manufacture of light emitting tube - Google Patents

Abstract

PURPOSE:To reliably seal a light emitting tube and to simplify its sealing by placing a frit on high melting point L-shaped metallic wires welded to a lower electric-supporting tube and then fusing the frit. CONSTITUTION:After electrode supporting tubes 3a and 3b are inserted into the holes of the sealing sections of a translucent ceramic tube 1, the tubes 3a and 3b are fused to the tube 1 by the use of frits 6a and 6b. During this process, two L-shaped Ta wires 5 are welded to the lower tube 3b in order to use the wires 5 as stoppers for adjusting the length of electrode protrusion and as frit stoppers. Due to the above structure, there is no possibility for the tube 3b to slant during sealing performed by fusing the frit 6b placed on the wires 5 and for the frit 6b to solidify in a lump, thereby highly reliably sealing the tube 1. Furthermore, the use of the wires 5 as both stoppers for adjusting the length of electrode protrusion and as frit stoppers saves material cost and increases efficiency of the manufacture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing an arc tube for a high-pressure sodium lamp, and in particular to a method for sealing an electrode support tube.

[Prior art and its problems] Conventionally, in high-pressure sodium lamps, chemical reactions between Na, which is added to the arc tube, and frit, which is a sealant, and physical diffusion of Na into the sealant occur. There is a phenomenon in which Na, which contributes to one luminescence, disappears from the arc tube. When this phenomenon occurs, the Na-
As the composition of Hg amalgam changes, the vapor pressure inside the arc tube changes, causing fluctuations in the electrical and optical characteristics of the lamp.
The effect of Na loss is small because approximately 0 times the Na content is encapsulated, but 1. For example, it was made to fit into a constant voltage rectangular ballast. In so-called unsaturated high-pressure sodium lamps filled with Na in an amount equal to or slightly larger than the amount of evaporation, or in high-color rendering high-pressure sodium lamps with Na vapor pressure increased to about 10 times the normal amount, the characteristics change significantly due to the disappearance of Na. Therefore, sufficient measures must be taken to prevent Na loss.

In general, N
a loss also tends to increase. Therefore.

Conventionally, in order to prevent the frit from being exposed inside the arc tube, sealing was carried out using the method shown in FIGS. 1 to 4. This is a method in which frit is filled between the electrode support tubes 3a, 3b made of Nb and the closure layer 4 by utilizing capillarity during sealing. In more detail, the first method is shown in Figures 1 and 2.
The figure shows the case where the arc tube is a so-called monolithic pipe type in which the translucent ceramic tube 1 and the closure body 4 are integrally formed. Figures 1 and 2 show a so-called open pipe type case formed by the closing bodies 4a and 4b.
As shown in the figure, the frits 6a and 6b are connected to the disk and T
The frits 6a and 6b are melted using scissors (the Ta plate serves as a frit stopper) between the members made of high melting point metal such as the a plates 5a and 5b plates.
In this method, when the electrodes a and 6b are melted, the Ta plates 5a and 5b are moved in parallel toward the disk to adjust the electrode protrusion length to a set value and perform sealing. However, in this method, the electrode support tube 3b may be sealed in an inclined state with respect to the ceramic tube 1, as shown in FIG. As a result, the sealing portion becomes extremely short in some parts, and the reliability of the seal becomes a problem.

Further, there is a drawback that the electrode protrusion length also differs from the set value.

Another method, as shown in FIGS. 3 and 4, is to place a flip 6a on top of the disks 4 and 4a, and
On the lower side, there is also a method of supporting the frit 6b using the Ta wire 9 as a slit stopper and sucking up the frit 6b. However, in this method, as shown in FIG. 8, the lower flip 6b does not get absorbed into the gap between the electrode support tube 3b and the translucent ceramic vibrator 1, and the slit stopper T a m 9 It may harden like a lump around the surface and cause a seal failure.

Further, in the conventional method, a frit stopper and a stopper for adjusting the length of the electrode protrusion (arousal tube stopper) are provided separately, so the structure is complicated.

[Object of the Invention] In order to eliminate the above-mentioned drawbacks, the present invention has been developed by welding two pieces of Ta wire to the lower Nb tube during sealing under the axial weight of the Nb tube, bending it into an Lp shape, and making the electrode protrude. Used as a stopper for length adjustment and a slit stopper, it is highly reliable (there are no short parts of the sealing part) and provides a reliable seal.It also serves as a stopper for adjusting the length of the electrode protrusion, making process work easier. The purpose is to simplify and reduce costs.

[Summary of the Invention] The present invention provides an electrode support tube in which an electrode support tube is inserted into the holes of both closed parts of a translucent ceramic tube, and the translucent ceramic tube and the electrode support tube are sealed with a frit. In the sealing method, at least two L-shaped fully bent wires made of high melting point metal are welded to the required positions of the lower electrode support tube, a frit is placed in the L-shaped part, and the This method of manufacturing an arc tube is characterized in that the electrode support tube and the closing body are sealed together after the frit is melted.

Here, the required position is when the electrode support tube is sealed so that the required electrode protrusion length is obtained.

This is the position where the required electrode protrusion length can be obtained.

[Embodiments of the Invention] FIGS. 5 and 6 are drawings showing embodiments of the present invention, in which 1 is a monolithic translucent ceramic tube, 1' is an oven-shaped translucent ceramic tube, and 2a is a monolithic translucent ceramic tube. , 2b is an electrode, 3
a, 3b are Nb tubes, 4a.

4b is a disk, 5 is a Ta wire, and 6a and 6b are frits.

As shown in FIG. 5, two L-shaped Ta wires 5 are welded to the lower Nb tube 3b during sealing and are used as a stopper for adjusting the length of the electrode protrusion and a frit stopper. With this configuration, during sealing, the electrode support tube 3b
Since the frit 6b is not tilted and the frit 6b is not hardened into a lump shape by passing through the Ta wire 5 which is the frit stopper/par, the accidents shown in Figs. 7 and 8 do not occur, and the As shown in the figure, highly reliable and reliable sealing can be performed. In addition, compared to the conventional method, since the stopper 2 (luminous tube stopper) for adjusting the length of the electrode protrusion and the 7-lift stopper are used together, less materials are required, labor is saved, and costs can be reduced and work efficiency improved.

The specific specifications of the lamps used in this example are as follows.

Lamp used: Normal 360W arc tube Alumina pipe with inner diameter 8.0φ Nb tube Φ Outer diameter 3.01φ Distance between Nb tube and disk: 0.045 mm (Nb tube touches disk on one side) 0.09mm) Diameter and length of L-shaped metal wire -0.1~0.2φ, 4~5
mm [Effect of the invention 1 As explained above, according to the method of the present invention, the sealing between the lower translucent ceramic tube and the closing body can be performed more reliably and reliably than with the conventional method. At the same time, costs and work efficiency can be improved.

[Brief explanation of drawings]

1 to 4, as well as FIGS. 7 and 8 are sectional views showing conventional examples, and FIGS. 5, 6, and 9 are sectional views showing embodiments. l... Translucent ceramic tube, 2a, 2b, electrode, 3a
...Upper electrode support tube (Nb tube), 3b...Lower electrode support tube (Nb tube), 4.-Closing body, 4a, 4b... Closing body (task cap), 5a, 5b*** Ta plate,
6a, 6ba'*s7 lit, 7a
, 7bth ・ :y lit
, 8a. 8b---stopper, 9...11 Ta wire.

Claims (1)

[Claims] 1. In a method for sealing an electrode support tube, the electrode support tube is inserted into holes in both closed parts of a translucent ceramic tube, and the translucent ceramic tube and the electrode support tube are sealed with a frit.
At least two L-shaped metal wires made of high-melting point metal were welded to the required positions of the lower electrode support tube, a frit was placed on the L-shaped portion, and the placed frit was melted. A method for manufacturing an arc tube, comprising: thereafter sealing the electrode support tube and the closure body.