JPH02215040A - High power low pressure discharge lamp - Google Patents

Abstract

PURPOSE:To eliminate the lower of the intensity of a caulking part of a filament and a supporting body thereof and obtain the stable lifetime characteristic by forming a filament supporting body with a metal having the easy processability and a high melting point. CONSTITUTION:A metal having the easy processability and a high melting point is used as a filament supporting body. For example, filament supporting bodies 114a, 114b are made of the tantalum Ta. A filament 112 is conducted with the light emitting current, and the emitter coating the filament is therefore evaporated to be flied. At this stage, the influence to the caulking intensity is not generated because the melting point of the tantalum Ta is 1996 deg.C, and the tantalum has also the fine processability and no trouble is generated at the time of manufacturing a mercury lamp. Thereby, the average lifetime of a high output and low pressure mercury lamp can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to high power low pressure discharge lamps, and in particular to improvements in the filament support thereof.

[Prior art] High-power low-pressure discharge lamps, such as mercury lamps that are lit at 1°5 W/cm or more, have advantages such as high germicidal radiation output, and are expected to be applied in various fields. .

FIG. 3 shows an electrode mount section 10 of such a conventional high-output, low-pressure mercury lamp.

In the figure, the electrode mount section 10 includes a filament 12 disposed in an arc tube (not shown), a filament support 14a that supports both ends of the filament 12,
14b, and an inscribed line 16 that supplies a light emitting current to the filament 12 via the filament supports 14a and 14b.
a, 16b.

The filament supports 14a and 14b are shown in FIG.
As shown in B), the filament 12 is fixed by caulking.

Incidentally, the filament support of conventional high-output, low-pressure mercury lamps generally uses nickel Ni wire.

This is because the inscribed wire 16 is made of molybdenum Mo or the like, and in order to connect the inscribed wire 16 and the filament support 14 by welding, weldability is good if the filament support 14 is made of Nf. , and filament 12
In order to fix the filament by caulking, the filament support must have some degree of flexibility, and N1 has excellent caulking properties.

Problems to be Solved by the Invention] However, when the filament support is made of Ni, there is a problem that normal arc discharge may not be sustained.

As a result of intensive research by the present inventors regarding this phenomenon, the following facts have become clear.

That is, for example, when a low-pressure mercury lamp is lit at high output, oxides such as barium Ba, calcium Ca, strontium Sr, etc., which are electron radioactive substances (emitters) coated on the filament, evaporate and scatter.

When the amount of emitter attached to the filament decreases, the filament temperature increases, which in turn induces an increase in the temperature of the filament support.

By the way, the melting point of Ni wire is relatively low at 1453°C, and as the lighting time increases, the strength of the caulked portion of the filament and filament support decreases, and sputtering occurs due to ion bombardment, leading to early disconnection, resulting in a stable lamp life. It becomes impossible to do so.

The present invention has been made in view of the problems of the prior art, and its purpose is to provide a high-output, low-pressure discharge lamp that can stably provide an appropriate lamp life.

[Means for Solving the Problems] In order to achieve the above object, the high output low pressure discharge lamp according to the present invention is characterized in that the filament support is made of an easily processable high melting point metal.

Note that tantalum Ta or the like is suitable as the easily processable high melting point metal.

[Function] As described above, in the high-output low-pressure discharge lamp according to the present invention, the filament support is made of an easily processable metal such as tantalum, so there is no problem in fixing the filament by caulking.

Furthermore, since the filament support is made of a high melting point metal, even if the emitter of the filament evaporates and scatters and the temperature of the filament and the filament support increases, the crimp strength will not be affected in any way.

Therefore, according to the high-output low-pressure discharge lamp according to the present invention, a suitable lamp life can be stably obtained without affecting manufacturability.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a high-output, low-pressure mercury lamp according to an embodiment of the present invention, and parts corresponding to those in FIG.
00 is added and the explanation is omitted.

The mercury lamp according to this embodiment, as shown in FIG.
Electrode mounts 110 are provided at both ends of the arc tube 100, and the main parts of the electrode mounts 110 are shown in FIG.

In the figure, an electrode mount section 110 is fixed to a quartz glass stem 120, and further fixed to a base 124 and an arc tube 100 via an adhesive 122.

On the other hand, the inscribed line 116a of the electrode mount section 110.

116b is connected to external tangent lines 128a, 128b via seal foils 126a, 126b.

The characteristic feature of the present invention is that an easily processable high melting point metal is used as the filament support, and for this reason, in this embodiment, the filament support 114a,
114b is made of tantalum Ta.

The high-output, low-pressure mercury lamp according to this embodiment is roughly constructed as described above, and its operation will be explained next.

The mechanism of light emission itself is the same as the conventional one, and the filament 11
A light emitting current is conducted to the filament 2, and the emitter coated on the filament is evaporated and scattered.

Then, the filament 112 and the filament support 1
The temperature of 14a and 114b increases, which causes a decrease in caulking strength in the conventional case.

However, in this example, the material of the filament support is tantalum, and the melting point is 1996° C., so there is no effect on the caulking strength.

Of course, tantalum has excellent processability and there are no problems when manufacturing mercury lamps.

As a result, the average lifespan of the high-output, low-pressure mercury lamp according to this embodiment is significantly improved.

FIG. 2 shows the survival rate of the product of this example and the conventional product depending on the lighting time, and the product of this example has almost 100% survival rate until the appropriate life. However, the conventional product has 1500
It is understood that the survival rate rapidly decreases after a certain period of time, and only a small percentage of the discharge lamp survives until its proper lifespan.

As described above, according to the product of this example, a highly stable, long-life, high-output, low-pressure mercury lamp can be obtained without deteriorating the processing characteristics.

[Effects of the Invention] As explained above, according to the present invention, since the filament support is made of an easily processable high melting point metal, there is no decrease in strength at the caulking portion between the filament and its support. Stable life characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a high-output low-pressure discharge lamp according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of the survival rate with respect to lighting time of the discharge lamp shown in FIG. 1 and a conventional discharge lamp, FIG. 3 is an explanatory diagram of the configuration of a conventional discharge lamp. 12.112...Filament 14.114...Filament support 26.126.
...Inscribed line patent applicant Iwasaki Electric Co., Ltd. 2, OOQ Figure 2 4.000 Lighting time (hr) Figure (A)

Claims (1)

[Claims] (1) A high-output low-pressure discharge lamp comprising: a filament disposed in an arc tube; a filament support supporting the filament; and an inscribed wire supplying a luminous current to the filament via the filament support. A high-output low-pressure discharge lamp characterized in that a filament support is made of an easily processable high-melting point metal.