JPH0447937B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a self-starting short arc rare gas discharge lamp used as a light source for optical communication of a flying object, etc., which is intended for one-time use. .

Conventional structure and its problems In self-starting short arc noble gas discharge lamps, the bridge wire connected between both electrodes generates arc light and is consumed by voltage application, and then maintains the main discharge. Take the startup method. Typically, the bridge wire is made of a high melting point metal such as molybdenum or tungsten ribbon. Short-arc rare gas discharge lamps without self-starting capability require a high-frequency voltage of 10 to 15 KV to start, whereas short-arc rare gas discharge lamps with self-starting function can be started at 100V. In order to
This has the advantage of simplifying the starting device and reducing costs. Since such a self-starting short arc rare gas discharge lamp has a structure that can be used only once, the reliability of its starting characteristics is an important issue. The shape and residual stress of the bridge wire are important factors in starting characteristics, and in order to obtain a discharge lamp with high reliability and uniform quality, it is necessary to establish a discharge lamp with a uniform bridge wire.

Referring to FIG. 1, the conventional method for manufacturing a self-starting short arc rare gas discharge lamp will be explained. As shown in FIG. obtain. Next, in FIG. 1b, the bridging wire 1 is positioned at a predetermined location between the cathode 2 and anode 3, and both ends 4 and 5 of the bridging wire 1 are welded using a spot welder or the like, and the cathode 2 and the anode are welded together. 3. Obtain an electrode body in which the bridging wire 1 is integrated.

Thereafter, this electrode body is inserted into a glass container (not shown) and the electrode body is sealed to both ends of the glass container. Then, in the evacuation step, the bridge wire is heated to the recrystallization temperature in a vacuum or inert gas to remove residual stress in the bridge wire generated during welding and sealing, and then a specified rare gas is filled. take the method of doing so.

In such conventional manufacturing methods, the following problems have occurred.

(1) Press-formed bridge wires tend to lose their shape during welding, which tends to cause variations in the starting characteristics of discharge lamps. That is, if the bridging wire is shaped to be spaced apart from the tip of the electrode, electric heating due to the energy generated when the bridging wire is fused is insufficient, resulting in startup failure. On the other hand, if it is too close to the tip of the electrode, the molten material of the bridging wire will adhere to the tip of the electrode, and the bright spot will not be concentrated during the main discharge, causing instability of the discharge and reduction in the amount of light.

(2) Skill is required to weld the press-formed bridging wire to a predetermined position between both electrodes, making it difficult to mechanize welding.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional problems, and it improves the reliability of the starting characteristics of the discharge lamp in a self-starting short arc noble gas discharge lamp having a bridge wire between both electrodes. The present invention also provides a method for manufacturing a self-starting short-arc rare gas discharge lamp, which enables mechanization of welding work and reduces the manufacturing cost of the discharge lamp.

Structure of the Invention The present invention connects a bridging wire in a linear shape to both electrodes and then molds it into a desired shape, or connects one end of a linear bridging wire to one electrode. Then, the electrode body is molded into a desired shape, the other end is connected to the other electrode, and the electrode body is heat-treated at a temperature of 800 to 1100°C in a reducing atmosphere, and this electrode body is attached to both ends of a glass container. It is designed to be sealed.

According to the manufacturing method of the present invention, since the bridging wire is molded after being connected to both electrodes, the bridging wire does not lose its shape during connection and can maintain a uniform shape. Furthermore, heat treatment in a reducing atmosphere after connecting the bridging wire to both electrodes has the effect of lowering the elastic modulus of the bridging wire and at the same time removing the residual stress generated during the molding process, so that the sealing work is easier. In addition to making it easier to seal, residual stress in the bridging wire after sealing is reduced.
This eliminates the problem of welding material sticking to the electrode tip and scattering toward the inner wall of the glass container during fusing. Furthermore, since the bridging wire is welded to both electrodes in a straight line, positioning becomes easy and mechanization of welding becomes easy.

Description of examples Examples of the present invention will be described below.

The method for manufacturing the self-starting short arc rare gas discharge lamp according to the embodiment of the present invention is as shown in FIG. 2a.
A straight bridging wire 6 is positioned at a predetermined location between the cathode 2 and the anode 3, and both ends 4 and 5 of the bridging wire 6 are connected by the cathode 2 and anode 3. Next, figure b
As shown in FIG. 2, the bridging wire 6 is molded into a desired shape using a press machine 7.

Thereafter, the integrated electrode body of the cathode 2, bridging wire 6, and anode 3 was heated for 800 min in a reducing atmosphere.
Heat at a temperature of ~1100°C. Then, the electrode body is inserted into a glass container (not shown), the cathode 2 and the anode 3 are sealed to both ends of the glass container, and in the evacuation step, the inside of the glass container is evacuated to a vacuum. A specified rare gas is sealed in it and chipped off.

As a spherical quartz glass container, outer diameter 9mm,
The anode diameter is 2 mm, the cathode diameter is 0.9 mm, the distance between the electrodes is 0.5 mm, and a molybdenum ribbon with a thickness of 20 μ and a width of 400 μ is used as the bridging wire. A self-starting short arc xenon discharge lamp was manufactured. Regarding the method of attaching a bridging wire made of molybdenum ribbon, first, both ends of a bridging wire cut to a length of about 6 mm are welded to the anode and cathode held with a gap of 0.5 mm. Thereafter, the bridging wire is molded into a desired shape. Since press molding and positioning are performed mechanically, a uniform shape and position can be obtained.

Then, the electrode with the bridge wire attached is heated at a temperature of about 800 to 1100°C in a hydrogen reducing atmosphere.
Heat treat for 15 minutes.

If the heat treatment temperature is less than 800°C, residual stress cannot be sufficiently removed. If the temperature exceeds 1100°C, the recrystallization temperature of molybdenum is 1150 to 1200°C, so it becomes brittle and the bridging wire is damaged during handling in the manufacturing process and during lighting of the discharge lamp.

In addition, heat treatment in a hydrogen-reducing atmosphere after welding removes the oxide film on the welded portion and has a gas release effect, which is useful for cleaning the electrode constituent materials.

After that, the electrode body that has gone through this process is inserted into a quartz glass container and sealed in a predetermined position.
After evacuating the inside to a high vacuum, xenon is filled in and chipped off.

In the discharge lamp obtained by the manufacturing method of the present invention, there is no need for removing residual stress in the bridging wire by heating with electricity or for discharging impure gas, as in the conventional method, in the main exhaust process.

When testing the starting characteristics of 30 self-starting short arc xenon discharge lamps manufactured by the manufacturing method of the present invention, it was found that after the bridging wire made of molybdenum ribbon generated arc light and was consumed by voltage application, The time it takes for the main discharge to move between the two electrodes is
The discharge time was 200 to 250 msec, which reduced the variation in discharge time, and mechanized welding work reduced the welding time by 50%.

On the other hand, when we tested the starting characteristics of 30 self-starting short arc xenon discharge lamps manufactured using conventional manufacturing methods, we found that the time it takes for the main discharge to transfer between the two electrodes is 150 to 600 msec. ,
Since the welding is done by hand and the shape of the bridge wire and welding position are uneven, there are large variations in starting characteristics between discharge lamps.

In addition, in the manufacturing method of the present invention, an experiment was conducted regarding the heating temperature in a reducing atmosphere.
If the temperature is below 800℃, the residual stress in the molybdenum ribbon bridging wire cannot be sufficiently removed, resulting in problems as high as 10%, such as molten matter adhering to the electrode tip or scattering on the inner wall of the glass container during fusing. did. In addition, if the temperature exceeds 1100℃, the molybdenum ribbon bridging wire becomes brittle, and there is a high rate of breakage of the bridging wire of 5% during the manufacturing process when inserting the electrode body into the quartz glass container and during sealing work. It occurred in Furthermore, in a drop impact test in which a discharge lamp was subjected to a fall impact acceleration of 100G, 3% of the bridge wires were damaged.

On the other hand, when the heating temperature in a reducing atmosphere was 800 to 1100°C, the above-mentioned problems were completely absent.
In addition, a self-starting short arc xenon discharge lamp was manufactured by the method of the present invention using a tungsten ribbon as the bridging wire, and the same test as in the case of the bridging wire made of the molybdenum ribbon was conducted. I got good results.

Furthermore, similar results were obtained in a self-starting short-arc krypton discharge lamp using krypton as the enclosed rare gas.

Next, in other embodiments of the present invention, FIGS.
To explain with reference to FIG. 3c, as shown in FIG. 9 to hold it on the anode 3 surface, and then the other end 10 of the bridging wire 6 is welded to the cathode 2 using a spot welder or the like. Then, as shown in FIG. 2B, the bridging wire 6 is molded into a desired shape using a press machine 7. Next, as shown in FIG. 3c, the presser lever is released and one end 8 of the bridging wire 6 that has been pressed is welded to the anode 3. Such a welding and forming procedure also provides excellent starting characteristics and enables mechanization of the welding operation.

Effects of the Invention As explained above, according to the method of the present invention,
The shape of the bridge wire is made uniform, residual stress is sufficiently removed, and the reliability of the starting characteristics can be improved.Furthermore, the positioning of the bridge wire with respect to the electrode is facilitated, making it easier for the machine to connect the two. is promoted,
A self-starting short-arc rare gas discharge lamp that can stabilize characteristics and reduce costs can be realized.

[Brief explanation of the drawing]

Figures 1a and b are process diagrams of a conventional method for manufacturing a self-starting short arc rare gas discharge lamp, and Figures 2a and b are diagrams of a self-starting short arc rare gas discharge lamp according to an embodiment of the present invention. 3A, 3B and 3C are process diagrams of a method of manufacturing a self-starting short arc rare gas discharge lamp according to another embodiment of the present invention. 2...Cathode, 3...Anode, 6...Bridging wire.

Claims (1)

[Scope of Claims] 1. After connecting in a straight line a bridging wire between a pair of electrodes to generate arc light and be consumed by voltage application and to generate a main discharge between the electrodes,
The bridging wire is molded into a predetermined shape, and then the pair of electrodes and the bridging wire are heat treated in a reducing atmosphere at a temperature in the range of 800 to 1100°C,
A method for manufacturing a self-starting short-arc rare gas discharge lamp, characterized in that the pair of electrodes is then sealed to both ends of a glass container. 2. When connecting a bridging wire between a pair of electrodes to generate arc light and be consumed by voltage application to produce a main discharge between the electrodes, one end of the bridging wire is connected to one of the electrodes. After connecting the bridging wire so that it forms a straight line, the bridging wire is formed into a predetermined shape, the other end of the bridging wire is connected to the other electrode, and then the pair The electrode and the bridging wire are heated to a temperature of 800 to
A method for manufacturing a self-starting short-arc rare gas discharge lamp, which comprises performing a heat treatment in a range of 1100°C, and then sealing the pair of electrodes to both ends of a glass container.