JPH0432151A - Metallic vapor discharge lamp - Google Patents

Abstract

PURPOSE:To prevent the temperature rise of the junction of a metallic foil conductor and an external lead, and to prevent the foil shortage and the breaking of a sealing tube by cutting the metallic foil conductor in an axial direction, and by connecting each of the cut metallic foil conductor with an intermediate lead. CONSTITUTION:Electrode mounts 3, 3 inserted into sealing tubes 2, 2 are formed out of an electrode shaft 5 provided with an electrode oil 4 on the point, a first metallic foil conductor 11 with which the base part of the electrode shaft 5 is welded, an intermediate lead 10 welded with the intermediate lead 10, a second metallic foil conductor 12 welded with the intermediate lead 10, and of the external lead 7 made of molybdenum and so on, welded with the metallic foil conductor 12. The metallic foil conductor is parted in an axial direction, and, since the metallic foil conductors thus parted are connected with each other through the intermediate lead, a contact area is small at the junction of the metallic foil conductor and the intermediate lead. The junction will be a thermal induction resistant point in the thermal induction route of the electrode mount, and the temperature rise of the junction of the metallic foil conductor and the external lead can thus be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Field of Industrial Application) The present invention relates to a small metal vapor discharge lamp applied to a small metal halide lamp or the like.

(Prior Art) Recently, there has been an increasing demand for high-intensity discharge lamps (HID lamps) to be used not only for wide-area lighting such as roads, plazas, and baseball stadiums, but also for indoor lighting such as stores. Since metal halide lamps have high efficiency and high color rendering properties, they are suitable for use in plazas, stadiums, etc., and are becoming increasingly popular.

A conventional metal halide lamp will be explained based on FIGS. 4 and 5.

In FIG. 2, reference numeral 1 denotes an arc tube bulb, which is made of transparent quartz glass. The bulb 1 has a substantially elliptical shape, and for example, in a lamp with a rated output of 2 KW, the outer diameter in the long axis direction is about 451 cm, and the outer diameter in the short axis direction is about 40'H.

Seal tubes 2.2 are connected to both ends of the valve 1, respectively. These sealing tubes 2.2 are also made of translucent quartz glass or hard glass, and are fused to both ends of the bulb 1 to communicate with the interior of the bulb 1.

Electrode mounts 3.3 are sealed in these sealed tubes 2.2.

As shown in FIG. 5, the electrode mount 3 includes a tungsten electrode shaft 5 having an electrode coil 4 made of tungsten or the like attached to its tip, and a base end of the electrode shaft 5 made of molybdenum or the like welded together. It consists of a metal foil conductor 6 and an external lead wire 7 made of molybdenum or the like bonded to the metal foil conductor 6.

Such electrode mounts 3, 3 are connected to sealing tubes 2, 2, respectively.
The electrode coils 4, 4 are exposed inside the bulb 1. Therefore, the electrode coils 4.4 are opposed to each other within the bulb 1 with a predetermined distance between the electrodes. In this state, the metal foil conductor 6 is sealed to the sealed tubes 2 by heating and melting the sealed tubes 2.2, and thereby the electrode mount 3 is supported by the sealed tube 2.

Inside the bulb 1, a metal halide such as SCl2, NaI, etc., mercury, and a starting rare gas such as argon, xenon, etc. are sealed.

To manufacture such an arc tube, first, the sealed tubes 2.2 are placed opposite the openings at both ends of the substantially elliptical bulb 1, and the sealed tubes 2.2 are heated using an oxy-hydrogen burner or the like. Airtightly weld to the openings at both ends of 1.

Next, electrode mounts 3 are placed inside these sealed tubes 2.2.
．． 3 and install it on the glass lathe.

At this time, the distance between the tips of the electrode shafts 5.5 is adjusted to a predetermined distance.

Operate the glass lathe and rotate bulb 1.
The sealed tube 2.2 is heated with an oxyhydrogen burner or the like while maintaining the inside in a vacuum or inert gas state. Sealed tube 2.
Since metal foil conductor 2 has a property that its diameter becomes smaller when it is heated and melted, the metal foil conductor 6 comes to be embedded in the sealing tube 2 in close contact with the metal foil conductor 6 due to this melting, thereby achieving an airtight seal.

After that, the inside of the valve 1 is evacuated through an exhaust tube (not shown) protruding from the valve 1, and SCl is added to the inside of the valve 1.
3. Complete the sealing of the exhaust tube by filling it with a metal halide such as NaI, mercury, and a starting rare gas such as argon or xenon.

(Problem to be Solved by the Invention) In a lamp having such a structure, the joints between the metal foil conductor 6 made of MO and the external lead wire 7 made of MO are exposed to the atmosphere, and these joints are connected to the respective electrodes. Since heat is conducted through the mount 3 and the sealing tube 2, the temperature rises.

Since this type of lamp has a high output, during lighting, the junction between the metal foil conductor 6 and the external lead wire 7 becomes high temperature due to the heat conduction, which makes it easy to oxidize, leading to melting or breakage of the junction. Furthermore, due to the difference in thermal expansion between the joint and the sealing tube 2, the sealing tube 2 may be damaged, which may lead to premature failure of the lamp.

In order to prevent such problems, conventionally, the length of the metal foil conductor 6 is increased to 60 mm or more, and therefore the length of the sealing tube 2.2 is set to 70 to 75 mm or more, thereby reducing the heat of the electrode. This makes it difficult for conduction to occur through the electrode mount 3 and sealing tube 2 to the joint between the metal foil conductor 6 and the external lead wire 7.

However, in this case, since the length of the metal foil conductor 6 becomes long, the foil tends to break when sealing with the sealing tube 2, and the sealing length of the metal foil conductor 6 and the sealing tube 2 increases. Since the tube is long, the difference in thermal expansion increases, causing distortion in the sealing tube 2.
This has drawbacks such as foil breakage and cracks in the sealing tube 2.

Furthermore, since the sealing tube 2.2 is required to be long, there is also the problem that the total length of the lamp becomes large.

The present invention was developed based on the above circumstances, and its purpose is to prevent temperature rise at the joint between the metal foil conductor and the external lead wire, as well as to prevent foil breakage and damage to the sealed tube. The object of the present invention is to provide a metal vapor discharge lamp in which the length of the sealed tube can be shortened.

[Structure of the Invention] (Means for Solving the Problems) The present invention divides a metal foil conductor into a plurality of pieces along the axial direction of a sealed tube, and connects an intermediate lead wire between these divided metal foil conductors. The present invention is characterized in that the end portion of the intermediate lead wire is attached to and joined to the metal foil conductor.

(Function) According to the present invention, the metal foil conductor is divided in the axial direction and the divided metal foil conductors are joined by the intermediate lead wire, so that the metal foil conductor and the intermediate lead wire come into contact at the joint location. The area becomes smaller. Therefore, this joint location becomes a heat conduction resistance location in the heat conduction path of the electrode mount, and it is therefore possible to prevent a rise in temperature at the joint portion between the metal foil conductor and the external lead wire. Furthermore, since the metal foil conductor is divided in the axial direction, the sealing area with the sealed tube becomes smaller, and it is possible to prevent foil breakage and damage to the sealed tube. If the temperature at the joint between the metal foil conductor and the external lead wire is kept at the same level as in the conventional case, the length of the sealing tube can be shortened.

(Example) The present invention will be described below based on a first example shown in FIGS. 1 and 2.

The drawings show a metal halide lamp with a lamp rated output of 2 KW, and members similar to the conventional ones shown in FIGS. 4 and 5 will be described with the same reference numerals.

The arc tube bulb 1 is formed of transparent quartz glass or hard glass into a substantially elliptical shape, and has an outer diameter in the long axis direction of 4511111% and an outer diameter in the short axis direction of 40 ml1, for example.
It has become a degree.

The sealing tube 2.2 connected to both ends of the valve 1 has an outer diameter of 8
IIlff11 consists of a quartz glass tube with a length of 70 to 75 mm.

The electrode mount 3.3 inserted through these sealed tubes 2.2 consists of an electrode shaft 5 with an electrode coil 4 attached to its tip, and a first metal foil conductor with the base end of the electrode shaft 5 welded together. 11, an intermediate lead wire 10 welded to the first metal foil conductor 11, a second metal foil conductor 12 welded to the intermediate lead wire 10, and a second metal foil conductor 12 welded to the first metal foil conductor 11. It is composed of an external lead wire 7 made of welded molybdenum or the like.

That is, in this embodiment, a conventional metal foil conductor 6 is divided in the axial direction to form a first metal foil conductor 11 and a second metal foil conductor 1.
The first metal foil conductor 11 and the second metal foil conductor 12 are connected by an intermediate lead wire 10.

The electrode shaft 5 is made of a tungsten wire with a wire diameter of 1.8+ am, and the tip of the electrode shaft 5 is made of a tungsten wire with a wire diameter of 1.8 am. The electrode coil 4 made of 0mm tungsten wire is wound in multiple turns.

The first metal foil conductor 11 and the second metal foil conductor 12 each have a thickness of 25 mm. The intermediate lead wire 10 is made of a tungsten wire with a wire diameter of 1.5 mm and a length of 30 m+a.

The distance from the tip of the first metal foil conductor 11 to the base end of the second metal foil conductor 12 is set to 60 am, which is equivalent to the length of the conventional metal foil conductor 6.

A joint between the electrode shaft 5 and the first metal foil conductor 11, a joint between the first metal foil conductor 11 and the intermediate lead wire 10, a joint between the intermediate lead wire 10 and the second metal foil conductor 12, and The joints between the second metal foil conductor 12 and the external lead wire 7 are connected by welding by attaching a wire to the metal foil, so that the metal foil and the wire are in line contact at these joints. ing.

For this reason, the cross-sectional area of the heat conduction path is small at these joint locations between the metal foil and the wire, and therefore, these locations become heat conduction resistance locations.

Such an electrode mount 3 is inserted into a sealed tube 2, and by heating and melting this sealed tube 2, the first metal foil conductor 1 is formed.
1 and a second metal foil conductor 12 are each closely embedded in the sealed tube 2, so that the electrode mount 3 is fixed and sealed to the sealed tube 2.

In this case, the first metal foil conductor 11 and the second metal foil conductor 1
2, that is, a sealed space 13 is formed around the intermediate lead wire 1o and the inner surface of the sealed tube 2.

The bulb 1 is filled with 500 mg of mercury, a metal halide consisting of 12H Sc I3 and 48 mg NaI, and a starting rare gas such as argon at 100 Torr.

The operation of the metal halide lamp having such a configuration will be explained.

The above-mentioned lamp is constructed by dividing a metal foil conductor in the axial direction and forming a first metal foil conductor 11 and a second metal foil conductor 12 which are divided into two.
Since these are connected by the intermediate lead wire 10, the number of joints between the metal foil and the wire increases. Since the metal foil and the wire are joined by welding with the end of the wire aligned with one surface of the metal foil, the two are almost in line contact, and the contact cross-sectional area is extremely small. Therefore, heat conduction from the wire to the metal foil and heat conduction from the metal foil to the wire are restricted at these locations where the contact cross-sectional area is small. In other words, resistance to heat conduction occurs at locations where the contact cross-sectional area is small, and the mutual heat conduction function decreases.

In the case of the conventional structure shown in FIGS. 4 and 5, the joints between the metal foil and the wire are the joint between the electrode shaft 5 and the metal foil conductor 6 and the joint between the metal foil conductor 6 and the external lead wire 7. There are a total of two locations, and when considering heat conduction to the joint between the metal foil conductor 6 and the external lead wire 7, there is only one heat conduction resistance location along the way.

On the other hand, in the case of this embodiment, the joint between the metal foil and the wire is the joint between the electrode shaft 5 and the first metal foil conductor 11;
A joint between the first metal foil conductor 11 and the intermediate lead wire 10,
This is the joint between the intermediate lead wire 10 and the second metal foil conductor 12 and the joint between the second metal foil conductor 12 and the external lead wire 7, and the joint between the second metal foil conductor 12 and the external lead wire 7. When considering heat conduction to parts, there are a total of three heat conduction resistance points along the way.

Therefore, during lighting, the rate of heat conduction from the electrode coil 4 to the joint between the second metal foil conductor 12 and the external lead wire 7 through the electrode mount 3 is reduced, and the second metal foil conductor 12
The temperature rise at the joint between the external lead wire 7 and the external lead wire 7 is suppressed.

Heat is conducted to the joint between the second metal foil conductor 12 and the external lead wire 7 not only through the electrode mount 3 but also through the tube wall of the sealed tube 2.

In this embodiment, since a sealed space 13 is formed between the first metal foil conductor 11 and the second metal foil conductor 12, that is, around the intermediate lead wire 10, a sealed tube surrounding this sealed space 13 is formed. The diameter of the tube wall 2 increases, and the surface area of this portion increases, that is, the heat dissipation area increases. Therefore, less heat is transmitted to the joint between the second metal foil conductor 12 and the external lead wire 7 through the tube wall of the sealed tube 2, and the temperature rise at this joint is suppressed.

If the joint between the second metal foil conductor 12 and the external lead wire 7 is exposed to the outside air, or if the temperature rise is regulated as described above, oxidation is prevented and this joint is prevented from fusing or breaking. .

Further, the difference in thermal expansion between the joint portion and the sealing tube 2 is reduced, and breakage of the sealing tube 2 can also be prevented.

Since the metal foil conductor is divided in the axial direction and consists of the first metal foil conductor 11 and the second metal foil conductor 12, the length of each metal foil conductor 11 and 12 can be shortened. The length of the sealing with the sealing tube 2 is shortened, and problems such as foil breakage during sealing are reduced, and the difference in thermal expansion is reduced, so the sealing tube 2 is not distorted, and foil breakage and sealing are reduced. Cracks in the pipe 2 are prevented.

Furthermore, if the temperature of the joint between the second metal foil conductor 12 and the external lead wire 7 is to be at the same level as the conventional one, the sealed tube 2
．． 2 can be set to 70 mm or less, and the lamp length can also be shortened.

The results of experiments conducted on the metal halide lamp having the configuration of the above embodiment will be explained.

Fifteen metal halide lamps with a rated output of 2KW were manufactured, and the metal foil conductors 11 and 12 were sealed when the electrode mount 3 was sealed.
When the sealing tube 2 was inspected for tears, cracks, and damage to the sealed tube 2, there were no occurrences of these defects.

This lamp was subjected to a repeated lighting test of 4 hours on and 30 minutes off at 2.4KW, which is 20% higher than the rated power.

Metal foil conductors 11 and 12 after 3000 hours of lighting
When the sealing tube 2 was inspected for tears, cracks, and damage in the sealed tube 2, there were no occurrences of these, and no poor bonding between the metal foil conductors 11 and 12 and the intermediate lead wire 1o or the external lead wire 7 was observed.

Note that these do not change even if the lighting direction is changed.

These experimental results also confirm the effects of the present invention.

Note that the present invention is not limited to the above embodiments.

That is, FIG. 3 shows a second embodiment of the present invention, in which a first metal foil conductor and a second metal foil conductor separated in the axial direction are metal foil conductors facing each other. 11a, llb and 12a, 12b, these metal foil conductors 11a, llb and 12a, 1
A quartz spacer 20, 21 is interposed between 2b.

Even with this configuration, heat conduction is restricted at the joints between the metal foil and the wire, compared to the conventional structure, so the temperature rise at the joints between the second metal foil conductors 12a, 12b and the external lead wire 7 is reduced. can be suppressed.

In this case, the first metal foil conductor and the second metal foil conductor are each separated, or each of the plurality of metal foil conductors 1
1a, llb and 12a.

12b, the mechanical strength of the electrode mount 3 is higher than that of the first embodiment.

Furthermore, the above embodiments are not limited to metal halide lamps, but can be applied to metal vapor discharge lamps having a structure in which a sealed tube is connected only to the end of the bulb, and an electrode shaft is inserted into the tube with a gap. is possible.

Further, the lamp described in the above embodiment may be used in a double tube structure by being housed in an outer tube.

[Effects of the Invention] As explained above, according to the present invention, the metal foil conductor is divided in the axial direction and the divided metal foil conductors are joined by the intermediate lead wire, so that the metal foil conductor and the intermediate lead are connected. The contact area becomes smaller at the joints of the wires. Therefore, this joint location becomes a heat conduction resistance location in the heat conduction path of the electrode mount, and it is therefore possible to prevent a rise in temperature at the joint portion between the metal foil conductor and the external lead wire. Furthermore, since the metal foil conductor is divided in the axial direction, the sealing area with the sealed tube becomes smaller, and it is possible to prevent foil breakage and damage to the sealed tube.

Furthermore, if the temperature at the joint between the metal foil conductor and the external lead wire is kept at the same level as in the past, there are advantages such as the ability to shorten the length of the sealing tube.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the present invention, FIG. 1 is a sectional view of a metal halide lamp, FIG. 2 is a perspective view showing the structure of an electrode mount, and FIG. 3 is a first embodiment of the present invention. 4 and 5 are cross-sectional views of one end side of the lamp showing the second embodiment.
The figure shows the structure of a conventional metal halide lamp.
FIG. 4 is a sectional view of the metal halide lamp, and FIG. 5 is a perspective view showing the structure of the electrode mount. DESCRIPTION OF SYMBOLS 1... Valve, 2... Sealed tube, 3... Electrode mount, 4... Electrode coil, 5... Electrode shaft, 7... External lead wire, 10... Intermediate lead wire , 11.12...
・Metal foil conductor. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 12 Figure 13

Claims (1)

[Claims] A sealed tube is connected to the end of the arc tube bulb, and an electrode mount consisting of an electrode shaft, a metal foil conductor, and a lead wire is inserted into the sealed tube, and the tip of the electrode shaft is inserted into the interior of the arc tube bulb. In a metal vapor discharge lamp in which the electrode mount is sealed in the sealed tube by melting the sealed tube while facing the ceiling, the metal foil conductor is divided into a plurality of pieces along the axial direction of the sealed tube. A metal vapor discharge lamp characterized in that an intermediate lead wire is spanned between the divided metal foil conductors, and an end of the intermediate lead wire is attached to and joined to the metal foil conductor.