JPH0427666B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a short arc rare gas discharge lamp used for plate making, optical communication, etc.

Conventional configurations and their problems Normally, in short-arc rare gas discharge lamps, such as short-arc xenon discharge lamps, the electrodes are hermetically sealed to the quartz glass container using fused silica glass using molybdenum foil with a thickness of 10 to 30 μm. Either by squeezing and sealing, or by fusing sealing glass to a metal encapsulating rod and wrapping it in glass.
It is sealed to quartz glass via a sealing glass. The former is applied to low-wattage discharge lamps of 150W or less, because there are limits to the allowable current value of the molybdenum foil, the temperature of the sealing part, and pressure resistance due to residual strain in the sealing part, and the latter is applied to high-wattage discharge lamps. Applied to discharge lamps.

First, with reference to FIG. 1, a conventional short arc xenon discharge lamp for direct current voltage lighting will be described in which a pair of electrodes are hermetically sealed via a molybdenum foil.

An anode 2 and a cathode 3 are hermetically sealed to both ends of the quartz glass container 1 with a distance between the electrodes of 0.5 to 2.5 mm via a metal foil 4 made of molybdenum, and an external lead wire 9 is connected to this. There are 10 inside
~20 atmospheres of xenon 5 is sealed. The anode 2 has a cut groove 6 having a curvature along the circumference at one end in order to reduce heat conduction of the electrode temperature to the sealed portion during operation of the discharge lamp. Further, a flat portion 7 is provided at the other end in order to facilitate welding with the metal foil 4 and to smooth the flow of fused silica glass during sealing.

Recently, short-arc xenon discharge lamps used for optical communication of flying objects are required to be downsized by reducing the size of the sealed part and to have impact resistance of 100 G or more when in flight. The conventional short arc xenon discharge lamp has the following problems.

(1) Since both ends of the cut groove 6 provided to reduce heat conduction to the sealed portion of the electrode form an acute angle, the tip of the electrode may break due to impact such as when flying.

(2) In order to prevent cracks in the quartz glass container 1 due to fusion between the electrode body and quartz glass during the sealing process, or cracks in the sealed portion due to thermal expansion of the electrode during operation, the electrode body There is substantially a gap 8 between the metal foil 4 and the quartz glass, and the electrode moves due to impact during flight, resulting in dislocation of the weld and cracking or cutting (hereinafter referred to as "cutting") of the metal foil 4.

(3) Downsizing due to reduction in the size of the sealed part causes the temperature of the sealed part to rise, which leads to oxidation of the metal foil in the sealed part and poor contact with external lead wires.

Purpose of the Invention The present invention has been made to eliminate the above-mentioned conventional problems, and is designed to provide a short-arc rare gas discharge lamp in which a pair of electrodes are sealed to a quartz glass container through metal foil. It also prevents the electrode from breaking, prevents the welding from coming off due to electrode movement, and prevents the metal foil from breaking. Furthermore, even when designing a compact discharge lamp, it does not cause oxidation of the metal parts at the sealing part or poor contact. The present invention provides an arc rare gas discharge lamp.

Structure of the Invention According to the present invention, a pair of electrodes are sealed to the ends of a quartz glass container via metal foil, and as the electrodes, at least one groove having a curvature is formed at one end, and the other end is formed with at least one groove having a curvature. The container is formed flat and has at least one recess formed in the flat part, and this recess is engaged with the inner surface of the sealing part of the quartz glass container, thereby providing excellent impact resistance. ,
In addition, oxidation of metal parts in the sealed portion is prevented.

FIG. 2 shows an embodiment of the present invention, in which a cut groove 11 provided on the circumference of one end of the electrode 10 has a radius of curvature r. The other end has a flat part 12, at least one recess 13 is formed in this flat part, and this recess 13 is engaged with the inner surface of the sealed part of the quartz glass container 14.

The outer diameter of the quartz glass container is 9 mm, the diameter of the anode is 2 mm,
Cut groove width 1mm and depth 0.5mm, radius of curvature r0.2
mm, width 1 and depth 0.3 of the recess around the flattened part
For DC voltage lighting with the structure shown in Figure 2, the diameter of the cathode is 0.9 mm, the pressure of the metal foil made of molybdenum is 25 μ, the distance between electrodes is 0.5 mm, the total length of the lamp is 42 mm, and the pressure is 15 atm/20°C with xenon sealed. A short arc xenon lamp was created. As a result of a repeated drop impact test of 10 times at 100G under no load, in the case of the conventional structure, 3 out of 30
In one case, the electrode broke, and in two cases, the metal foil broke due to electrode movement. Since the electrode had an acute angle, no electrode breakage occurred. In addition, since the electrode and a portion of the quartz glass were engaged, there was no electrode movement and no problems occurred among the 30 electrodes.

Next, as a result of a 2-minute test of 13G random vibration at a 60W load with a lamp current of 6A and a lamp voltage of 10V, in the case of the conventional structure, 2 out of 25 lamps turned off due to breakage of the metal foil due to electrode movement. . On the other hand, in the case of the structure according to the present invention, such defects did not occur at all among the 30 samples.

Next, under the above conditions, the temperature near the connection between the metal foil of the sealed part and the external lead wire under load is 420°C when stable in the case of the conventional structure, and 4 out of 23 wires are connected to the metal foil and the external lead wire. The welded part with the wire was oxidized, and unstable discharge was observed due to poor contact. In contrast,
In the case of the structure according to the present invention, since the concave portion was formed in the flat portion, heat conduction from the electrode was reduced, the temperature rise at the end of the sealing portion was reduced, and no problems occurred at 350° C.

Furthermore, the outer diameter of the quartz glass container is 15 mm, the diameter of the anode is 2.5 mm, the width of the kerf is 1.5 mm and the depth is 0.7 mm, the radius of curvature is 0.7 mm, the width of the recess around the flattened part is 2 mm and the depth is 0.5 mm, and the cathode is 1.2 mm. mm, the thickness of the metal foil made of molybdenum is 25μ, the distance between electrodes is 2.0mm, and the total length of the lamp is 70mm.
A short-arc xenon discharge lamp for DC voltage lighting was created with a xenon sealed pressure of 13 atm/20°C. Drop impact test with no load, and lamp current 6.5A,
A random vibration test at a lamp voltage of 15.5V and a load of about 100W and a temperature test at the end of the sealing part showed similar trends to the results above when compared with conventionally structured discharge lamps.

In the embodiment shown in FIG. 2, the recesses 13 are formed on the flattened side surface, but as shown in FIG. 3, they can also be formed on the flattened side surface.

Forming a recess on a part of the electrode body or on the circumference,
When we tested this on a discharge lamp that was engaged with the inner surface of the sealed part of a quartz glass container, we found that the electrode was overheated by the heat of the quartz glass, and during the engagement operation, the quartz glass container and the electrode body were fused. , a crack occurred in the quartz glass.

In addition, for those with a bulge formed around the flat part of the electrode, or those with a protrusion formed on the electrode surface by welding a metal piece, the inner surface of the sealing part between the bulge or protrusion and the quartz glass container. An experiment was conducted to see the effect of engagement with the electrode, and although it was possible to prevent the electrode from moving due to engagement, it was not possible to reduce heat conduction from the electrode when the discharge lamp was loaded.

Effects of the Invention As explained above, the present invention has a pair of electrodes sealed to both ends of a quartz glass container via metal foil, and the electrode has at least one cut having a curvature at one end. A groove is formed, the other end is formed flat, and at least one groove is formed in the flat part.
Since this recess is engaged with the inner surface of the sealing part of the quartz glass container, even if the impact is dropped over 100G, there is no possibility of welding coming off or the metal foil breaking due to electrode bending or electrode movement. Furthermore, it is possible to provide an impact-resistant short-arc rare gas discharge lamp that does not cause oxidation of metal parts or poor contact in the sealed portion even when designing a discharge lamp to be more compact.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway sectional view of a conventional short arc rare gas discharge lamp, Fig. 2 is a sectional view of a main part of a short arc rare gas discharge lamp which is an embodiment of the present invention, and Fig. 3 is a sectional view of a main part of a short arc rare gas discharge lamp according to the present invention. It is a figure which shows the other example of the electrode concerning this. 11... Cut groove, 12... Flat part, 13... Concave part, 14... Quartz glass container.

Claims (1)

[Claims] 1 A pair of electrodes are sealed to the ends of a quartz glass container via metal foil, and the electrodes have at least one cut groove having a curvature formed at one end, and the other end is formed flat. At least one
A short-arc rare gas discharge lamp characterized in that a recess is formed therein, and the recess is engaged with an inner surface of a sealed portion of the quartz glass container.