JP4862240B2 - Method for manufacturing metal vapor discharge lamp and metal vapor discharge lamp - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal vapor discharge lamp having an electrode system in which a metal material is resistance-heat-welded to a conductive cermet and an improvement of the manufacturing method thereof.
[0002]
[Prior art]
Recently, a metal vapor discharge lamp called a ceramic metal halide lamp using a ceramic arc tube is replacing a conventional product using a quartz arc tube.
[0003]
The arc tube and the narrow tube made of ceramic are mainly made of alumina, and mercury, metal halide, starting rare gas and the like are enclosed in the arc tube. An electrode system is inserted on both sides of the capillary tube, and the capillary tube ends are sealed with glass frit.
[0004]
The electrode system is configured by welding a tungsten electrode and a halogen-resistant intermediate material and a current supply conductor or a tungsten electrode and a current supply conductor. Niobium is often used for the current supply conductor. Niobium has a coefficient of thermal expansion close to that of alumina among refractory metals, and is most suitable as an electrode material used for the seal portion.
[0005]
However, since niobium reacts with halides in the arc tube and is easily corroded, conductive cermets have recently been used as a material for current supply conductors instead of niobium (Japanese Patent Laid-Open No. 2000-113859). ).
[0006]
The conductive cermet is a sintered body of ceramics and metal, and a typical example is one made of alumina and molybdenum. When the content ratio of alumina in the conductive cermet is increased, the difference in thermal expansion coefficient from the luminous tube made of alumina can be reduced, and the generation of cracks from the thin tube can be suppressed. In addition, since alumina and molybdenum are both halogen-resistant materials, there is no risk of being corroded by the halide in the arc tube. Further, since the conductive cermet reacts well with the glass frit at the time of sealing and forms a strong bond, there is no possibility of arc tube leakage from the interface between the conductive cermet and the glass frit.
[0007]
[Problems to be solved by the invention]
When the conductive cermet is used as a current supply conductor of the electrode system of the arc tube made of alumina, the metal material 51 is resistance-welded to the conductive cermet 52 as a stopper for determining the insertion length of the electrode system as shown in FIG. To do. Also, when the arc tube is welded to the column, resistance heating welding is performed on the end of the conductive cermet in order to use the metal material as the external lead.
[0008]
The metal component contained in the conductive cermet is molybdenum or tungsten. Since the ceramic component alumina contained in the conductive cermet has a lower melting point than the metal component contained in the conductive cermet and the metal material, the alumina melts when the metal material 51 is resistance-welded to the conductive cermet 52. And adheres to the electrode rod 53b of the resistance heating welder.
[0009]
For this reason, the conductivity of the surface of the electrode rod 53b of the resistance heating welder is impaired, and there arises a problem that sufficient welding strength cannot be obtained. If the welding operation is continued as it is, no current flows between the electrode rods 53a and 53b of the resistance heating welder, and the metal material 51 and the conductive cermet 52 cannot be welded. . In order to prevent this from happening, it is necessary to scrape off the alumina adhering to the surface of the electrode rod 53b of the resistance heating welder during the welding operation, resulting in poor working efficiency when the metal material and the conductive cermet are resistance heating welded. .
[0010]
In addition, when the metal material 61 as a stopper is welded only to one side of the conductive cermet 62 as shown in the cross-sectional view and the transverse cross-sectional view of the narrow tube end portion shown in FIGS. 6 (a) and 6 (b), Since the conductive cermet 62 is inclined with the metal material 61 as a fulcrum, the central axis of the electrode system is inclined, and the thickness of the glass frit 64 becomes uneven when sealing the end of the thin tube 63, and when sealing or lighting. There is also a problem that cracks occur.
[0011]
Further, when the arc tube is welded to the support column, it is necessary to resistance-weld a refractory metal material as an external lead to the end portion of the conductive cermet. The external lead is often made of niobium having a malleability and having a thermal expansion coefficient close to that of alumina in consideration of disconnection of welding due to lighting or external impact. In this case as well, there is a problem that alumina is melted from the conductive cermet and adheres to the electrode rod of the resistance heating welder.
[0012]
Therefore, in the present invention, when the metal material as an electrode system and the conductive cermet are resistance-heat-welded, the ceramic component in the conductive cermet and the metal material are well welded, and welding with high reliability without misalignment is performed. Metal vapor discharge lamp having an electrode system in which welding work efficiency is remarkably improved and the ceramic component in the conductive cermet does not adhere to the electrode rod of the resistance heating welder, its manufacturing method, and electrode system An object is to provide a welding method.
It is another object of the present invention to provide a metal vapor discharge lamp, a method for manufacturing the same, and a method for welding the electrode system, which do not cause cracks in the capillary tube due to the inclination of the center axis of the electrode system, particularly the conductive cermet.
[0013]
[Means for Solving the Problems]
In order to achieve this object, the invention of claim 1 includes an electrode system composed of an electrode, a halogen-resistant intermediate material, and a conductive cermet, and an arc tube body formed of ceramics and thin tubes at both ends thereof. In a method for producing a metal vapor discharge lamp, which is inserted into a thin tube of a luminous tube and sealed at the end of the thin tube, the melting point higher than the melting point of the ceramic component contained in the conductive cermet. When the metal material having resistance is heated by resistance , the metal material includes a step of resistance welding so as to sandwich the conductive cermet without directly contacting the electrode of the resistance heating welder and the conductive cermet.
[0014]
According to a second aspect of the present invention, there is provided a metal vapor discharge lamp comprising an arc tube body formed of ceramics, an arc tube having thin tubes at both ends thereof, an electrode, a halogen-resistant intermediate material, and a conductive cermet. In a metal vapor discharge lamp in which an electrode system is inserted into the narrow tube and the end of the thin tube is sealed, the conductive cermet is axially disposed at the end of the conductive cermet of the electrode system. On the other hand, metal materials having a melting point higher than the melting point of the ceramic component contained in the conductive cermet substantially vertically are opposed to each other and welded by resistance heating.
[0017]
That is, according to the invention described in each claim, the ceramic component and the metal material in the conductive cermet are well welded, and it is possible to perform highly reliable welding without deviation of welding, and the work efficiency of the welding is remarkably improved. An improved metal vapor discharge lamp having an electrode system in which the ceramic component in the conductive cermet does not adhere to the electrode rod of the resistance heating welder, a manufacturing method thereof, and a welding method of the electrode system are obtained.
In addition, a highly reliable metal vapor discharge lamp that does not cause cracks in the seal portion due to the inclination of the central axis of the conductive cermet as the electrode system, a method for manufacturing the same, and a method for welding the electrode system can be obtained.
[0018]
【Example】
Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.
FIG. 1 is an explanatory view of resistance heating welding of a conductive cermet 1 and a metal material 2.
The niobium lead as the metal material 2 is disposed so as to be opposed substantially perpendicular to the axial direction of the conductive cermet 1, and the conductive cermet 1 and the metal material 2 are welded by the electrode rods 3a and 3b of the resistance heating welder. This prevents the ceramic component in the conductive cermet 1 from adhering to the electrode rod 3 of the resistance heating welder, so that the conductive cermet 1 and the electrode rods 3a, 3b of the resistance heating welder do not come into contact with each other. The conductive cermet 1 is sandwiched and welded with a kind of niobium metal.
[0019]
At this time, the melting point of the ceramic component (alumina) contained in the conductive cermet 1 is lower than the melting point of the metal component (molybdenum) contained in the conductive cermet 1 and the melting point (niobium) of the metal material 2. Since the metal material 2 is sandwiched between the conductive cermet 1 and welded substantially perpendicularly to the axial direction of the conductive cermet 1, the ceramic component in the conductive cermet 1 and the metal material 2 are well welded and welded. It is possible to perform reliable welding without detachment, and the work efficiency of welding is also greatly improved.
Moreover, the ceramic component in the conductive cermet 1 does not melt and adhere to the electrode rod 3 of the resistance heating welder.
[0020]
The arc tube is configured by inserting an electrode system into an arc tube body formed of ceramics and narrow tubes provided at both ends thereof, and sealing the ends of the narrow tubes.
By the metal material (niobium lead) 2 that plays the role of a stopper that regulates the insertion length welded as described above, as shown in the sectional view and the transverse sectional view of the end of the thin tube shown in FIGS. The central axis of the conductive cermet 1 and the central axis of the thin tube 4 are on the same axis, so that the electrode system does not tilt.
Therefore, when the end of the thin tube 4 is sealed, the thickness of the glass frit 5 is also uniform, and cracks are not generated during sealing or lighting.
[0021]
Further, since the temperature when the glass frit 5 is melted and the thin tube 4 is sealed is 1400 ° C. or higher, the metal material 2 needs to be a refractory metal that does not melt at the sealing temperature. Examples of 2 include molybdenum, tantalum, tungsten, and the like, and the shape may be any of rod, plate, foil, wire, pipe, and tube.
[0022]
When the metal vapor discharge lamp is combined with the outer sphere, a metal material is welded to the end of the conductive cermet 1 by resistance heating welding as shown in FIG. 3 to form the external leads 6a and 6b. Also in this case, since the metal material is welded with the conductive cermet 1 sandwiched in the axial direction of the conductive cermet 1, the ceramic component in the conductive cermet 1 melts and adheres to the electrode rod of the resistance heating welder. Disappears. The metal material may have any shape of rod shape, plate shape, foil shape, wire shape, pipe shape, and tube shape.
[0023]
As shown in FIG. 4, the arc tube is held via a support column 9 in an outer sphere 8 having a base 7 fixed to one end. The external leads 6 a and 6 b welded to the end portion of the conductive cermet 1 are welded to the support of the support column 9 and joined.
[0024]
【Effect of the invention】
As described above, according to the present invention, the conductive cermet and the metal material are firmly welded by resistance welding, and it is possible to perform highly reliable welding without deviation of welding, and the work efficiency of the welding is remarkably improved. The metal vapor discharge lamp, the manufacturing method thereof, and the welding method of the electrode system can be obtained which have the advantage that the ceramic component in the conductive cermet is not attached to the electrode rod of the resistance heating welder.
In addition, a highly reliable metal vapor discharge lamp that does not cause cracks in the seal portion due to the inclination of the central axis of the electrode system, particularly the conductive cermet, a manufacturing method thereof, and a welding method of the electrode system can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory view of an electrode manufacturing method by resistance heating welding according to the present invention. FIG. 2 is a cross-sectional view and a cross-sectional view of an end of a thin tube.
FIG. 3 is a side view in which an external lead is welded to an end portion of a conductive cermet when a ceramic arc tube and an outer sphere are combined.
FIG. 4 is a metal vapor discharge lamp according to an embodiment of the present invention.
FIG. 5 is an explanatory diagram of a conventional electrode manufacturing method using resistance heating welding.
FIG. 6 is a cross-sectional view and a cross-sectional view of an end of a thin tube of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Conductive cermet 2a, 2b Metal material 3a, 3b Electrode rod of resistance welding machine 4 Thin tube part of arc tube 5 Glass frit 6a, 6b External lead 7 Base 8 Outer ball 9 Post

Claims (2)

An electrode system composed of an electrode, a halogen-resistant intermediate material, and a conductive cermet is inserted into an arc tube main body made of ceramics and an arc tube having capillaries at both ends, and an end portion of the capillaries In the manufacturing method of the metal vapor discharge lamp formed by sealing
When the metal material having a melting point higher than the melting point of the ceramic component contained in the conductive cermet is resistance-heated to the conductive cermet, without directly contacting the electrode of the resistance heating welder and the conductive cermet , The method of manufacturing a metal vapor discharge lamp, wherein the metal material includes a step of resistance welding so as to sandwich a conductive cermet . An arc tube body formed of ceramics, an arc tube having a thin tube at both ends thereof, and an electrode system composed of an electrode, a halogen-resistant intermediate material, and a conductive cermet, and the electrode system is inserted into the narrow tube In the metal vapor discharge lamp in which the end of the thin tube is sealed, the end of the conductive cermet of the electrode system is contained in the same conductive cermet substantially perpendicular to the axial direction of the conductive cermet. A metal vapor discharge lamp, characterized in that metal materials having a melting point higher than that of the ceramic component are welded to each other by resistance heating.

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