JPH03210747A - Single-sealed metal-vapour discharge lamp - Google Patents

Abstract

PURPOSE:To widen an interval between each electrode point part without changing the size of a sealed part by arranging the point parts of the electrodes in different directions from one another to a flat surface including a pair of shaft parts. CONSTITUTION:Shaft parts 4 of a pair of electrodes 3 are sealed almost in parallel to a pressed sealed part 2 of an emission tube 1, so as to arrange the electrodes 3 in a separated manner in the width direction of the sealed part 2, while point parts 5 of the electrodes 3 are opposed in such a manner that they are bent in the direction where the shaft parts 4 are extended, so as to maintain the safety of discharging. When the angle of the bending exceeds thirty degrees, the inner wall surface of the emission tube and an arc are approached with one another, whereby devitrification of the material of the emission tube is generated. When it less than five degrees, the changing ratio between an interval between the point parts at the initial stage of lamp life, and that in the middle of lamp life, concomitant with electrode splash, is increased. For this reason, the bending angle is preferred to be five to thirty degrees. By bending the point parts 5 in different directions from each other, the interval between the electrode point parts can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a single-sealed small metal vapor discharge lamp that is applied to a small metal halide lamp or the like.

(Prior art) In recent years, small metal vapor discharge lamps used for indoor and outdoor lighting have been developed, and recently a so-called single-sealed lamp has been developed, in which a pair of electrodes is sealed only at one end of the arc tube. A shape structure is being considered.

This single-sealed lamp has been considered in the past.

As shown in FIG. 3, a predetermined amount of mercury, metal halides such as sodium, thallium, and indium, and a starting rare gas are sealed inside the arc tube 11 having an approximately ellipsoidal discharge space. .

Also, a sealing part 1 located at one end of the arc tube 11
2 includes a pair of electrodes 1 consisting of an electrode shaft portion 13 and an electrode tip portion to which a coil 14 is fixed to increase heat capacity.
5 is sealed.

The electrode shaft portions 13 are respectively connected to metal foil conductors 16 made of molybdenum or the like sealed to the crushing sealing portion 12, and the electrode tip portions 14 are arranged in the extending direction of the electrode shaft portion 13 so that the two face each other. The structure is such that the discharge occurs between the two bends.

(Problem to be Solved by the Invention) Generally, if the distance between the electrodes can be increased, the lamp voltage can be increased accordingly, so it is desirable to increase the distance between the electrodes even if only slightly. ,
In the case of the arc tube with the above structure, two metal foil conductors are juxtaposed and sealed in a sealing part provided only at one end, and the sealing part is in the width direction of the arc tube in order to miniaturize the entire arc tube. The size cannot be increased, and the width of the sealing part cannot be increased by increasing the distance between the two metal foil conductors. Trying to increase the distance is difficult.

Furthermore, the electrode of the single-sealed metal vapor discharge lamp is bent in the direction of extension of the electrode shaft so that the tip ends face each other in order to maintain stable discharge at the tip. Therefore, there was a problem in that it was extremely difficult to increase the distance between the electrode tips.

The present invention aims to provide a single-sealed metal vapor discharge lamp in which the distance between the electrode tips can be increased without changing the size of the sealing part.

[Structure of the Invention] (1) (Means for Solving the Problems) In order to solve the above problems, the single-sealed metal vapor discharge lamp of the present invention includes an electrode shaft portion and a tip portion bent from the electrode shaft portion. A single-sealed metal vapor discharge lamp having a crushing seal formed at one end for sealing a pair of electrodes each having The tip portions of the electrodes are disposed in different directions with respect to a plane including the pair of shaft portions.

(Function) In the present invention, since the tips of the electrodes are disposed in different directions with respect to the plane including between the electrode shafts, the gap between the tips of the electrodes can be improved without changing the size of the sealing part. It is possible to provide a single-sealed metal vapor discharge lamp that can extend the distance.

(Example) An example of the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, an embodiment of a single-sealed metal vapor discharge lamp with a lamp input power of 150 W according to the present invention, a predetermined amount of mercury, metal halides such as sodium, thallium, and indium, and a starting material are used. The arc tube 1 is made of a heat-resistant and transparent material such as quartz, and has an internal volume of approximately 0.
．． It has an approximately ellipsoidal discharge space of 5 CC, and a crushing sealing portion 2 is provided at one end of the bulb in the short direction.

Further, the shaft portions 4 of the electrodes are each sealed substantially parallel to the crushing sealing portion 2 so that the pair of electrodes 3 are disposed apart in the width direction of the crushing sealing portion 2 of the arc tube l, and The tip portion 5 of the electrode 3 is bent to face the extending direction of the electrode shaft portion 4 in order to maintain stable discharge, and is arranged at a horizontal distance from the electrode shaft portion 4 in the direction of the opposing electrode. It has a length of 1.711.

Here, a coil 6 made of, for example, tungsten with a wire diameter of 0-5-5 or thoriated tungsten containing about 2% thorium is wound around the tip 5 of the electrode 3 in order to increase its heat capacity. The electrode shaft portion 4 has a wire diameter of 0.
．． The conductors are made of rhenium or rhenium-tungsten alloy, and their ends are respectively connected to crush-sealed metal foil conductors 7 made of, for example, molybdenum.

As shown in FIG. 2, the tip portions 5 of the electrodes 3 are bent in different directions by an angle of, for example, about 20 degrees with respect to the plane containing the pair of electrode shaft portions 4, so that the tip portions of the electrodes are bent at the shortest distance. The distance is 6.4u+.

On the other hand, as a reference example, we use a conventional single-sealed metal vapor discharge lamp of the same type in which the tip is located on the plane containing the electrode shaft, that is, it is not bent with respect to the plane containing the electrode shaft. When created, the shortest distance between the tips of the electrodes was 6-2-
Met.

According to experiments conducted by the inventors, if the bending angle exceeds 30°, the inner wall surface of the arc tube and the arc may come close to each other, causing devitrification of the arc tube material.If the bending angle is less than 5°, the lamp life may be shortened. It has been confirmed that the ratio of change in the initial distance between the tips and the distance between the tips due to electrode scattering during the life of the lamp increases, and therefore the change in lamp characteristics during the life of the lamp tends to increase.

Therefore, it is preferable that the bending angle is set within a range of 5° to 30° with respect to the plane including the electrode shaft portion.

According to the above embodiment, since the tips of the electrodes are bent in different directions with respect to the plane including the electrode shaft, the distance between the tips of the electrodes is larger than that of a conventional single-sealed metal vapor discharge lamp. be able to.

In addition, since the tips of the electrodes are simply bent in different directions with respect to the plane containing the electrode shaft, the distance between the electrode tips can be increased without changing the size of the crush sealing part. .

In the above embodiments, the tip portions of the electrodes are bent by equal amounts in different directions with respect to the plane including the electrode shaft portion, but the present invention is not limited to this. , for example, by making the bending angles of the electrode tips different for both electrodes, or by rotating and twisting the electrode shaft, the electrode tips are positioned in different directions with respect to the plane containing the electrode shaft. It may be.

[Effects of the Invention] According to the present invention described above, a crushing sealing portion is formed at one end to seal a pair of electrodes each having an electrode shaft portion and a tip bent from the electrode shaft portion, and This is a single-sealed metal vapor discharge lamp equipped with an arc tube filled with a rare gas, a luminescent metal, and mercury, and the tips of the electrodes are arranged in different directions with respect to the plane containing the pair of shafts. Therefore, the distance between the electrode tips can be increased without changing the size of the sealing part.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a single-sealed metal vapor discharge lamp according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the single-sealed metal vapor discharge lamp shown in FIG. FIG. 3 is a schematic diagram of a conventional single-sealed metal vapor discharge lamp. 1.11... Arc tube 2,12...
Crushing sealing part 3.15... Electrode 4.13-
... Electrode shaft part 5.14 ... Tip part

Claims (1)

[Claims] A crushing sealing part is formed at one end to seal a pair of electrodes each having an electrode shaft part and a tip bent from the electrode shaft part, and a light emitting device in which a starting rare gas, a luminescent metal, and mercury are sealed. A single-sealed metal vapor discharge lamp equipped with a tube, characterized in that the tip portions of the electrodes are disposed in different directions with respect to a plane containing the pair of shaft portions. shaped metal vapor discharge lamp.