JPS6335485Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Technical field of invention] This invention relates to improvements in water-cooled discharge lamps.

[Background technology of the invention and its problems]

FIG. 1 shows a conventional water-cooled discharge lamp 1, in which metal end caps 3a and 3b are attached to both ends of a straight tube 2 made of quartz cut to a predetermined length according to the emission length. A cathode 6 and an anode 7, which are integrated with external electrodes 4 and 5, respectively, penetrate through the end caps 3a and 3b and face each other inside a straight tube 2 sealed with a predetermined gas. This type of discharge lamp is a solid-state laser device, which is water-cooled and applies a high voltage to optically excite the laser material. However, if the operating time is less than 100 hours, phenomena such as the straight pipe 2 cracking, discharge not starting even when a trigger voltage is applied, leaking of the sealed gas, and intrusion of cooling water from the outside occur.

These phenomena are disadvantageous in practical use of discharge lamps. The above phenomenon is likely to occur because the discharge lamp 1 is in operation underwater.

[Purpose of invention]

This invention provides a long-life discharge lamp.

[Summary of the idea]

The end cap has a structure in which the electrode rod that comes out from the quartz straight pipe is surrounded by a metal body, and the outer surface of the end cap is protected with an insulating layer to prevent corrosion of the end cap body and the penetrating parts. This is what I did.

[Example of idea]

FIG. 2 shows a water-cooled discharge lamp 10 which is an embodiment of this invention, and parts common to those in FIG. 1 are given the same reference numerals and will be explained. Metal cylindrical bodies 12a and 12b are fixed to the outer surfaces of both ends of the straight pipe 11 by fitting parts of them. 11 and 12a, 1
This fixation between the parts 2b is achieved by pouring solder containing indium, lead, etc. as a main component. Disk plates 13a and 13b, which serve as partition walls, are fixed to the middle of these cylindrical bodies 12a and 12b, and the cathode 6 and anode 7, which are integrated with the external electrodes 4 and 5, are provided by penetrating these disk plates 13a and 13b. ing. Further, the straight pipe 11 adjacent to the outer surface of the cylindrical bodies 12a, 12b and the fixed portion between these cylindrical bodies and the straight pipe 11
An insulating coating layer 14 is formed on a part of the outer surface of. This covering layer is formed by winding Teflon (trade name) tape, coating with silicone resin, or using a heat-shrinkable resin tube.

With the above configuration, since each external electrode 4, 5 does not have an insulating coating layer, it is easy to supply power from the outside, and cooling efficiency is good because the cooling water acts directly on the external electrodes 4, 5. In addition, even if a high voltage is applied to the external electrodes, the back surface of each cylinder 12a, 12b and the outer surface of each disk 13a, 13b form a space closed in three directions.
Since no strong electric field is applied to the surfaces of a and 13b during water cooling, no strong electrolysis is applied even if the electrical conductivity decreases, making it difficult for electrolytic corrosion to occur. Furthermore, the insulating coating layer 14 makes it difficult for corrosion to occur in the connecting portions of the cylindrical bodies 12a, 12b and the straight pipe 11, as well as the outer walls of the cylinders 12a, 12b, and the outer walls of the cylinders 13a, 13b, even under water-cooled operating conditions.

[Effect of idea]

Corrosion prevention has been further improved and pinholes are no longer formed in the metal parts, so there is no longer any leakage of the filled gas or the intrusion of cooling water into the interior of the discharge lamp, and there is no particular problem in terms of cooling efficiency. The lifespan of the discharge lamp has been extended without this problem.

In order to compare the lifespan, the above configuration and the conventional one were installed in the laser head, the cathode and the elliptical reflector in the laser head were set at the same potential, and a DC voltage of 2000 V was applied between the anode and the laser head, and the two were cooled with water. When we tested the conventional model, no discharge occurred and leakage occurred 6 to 12 hours after applying the trigger, but the insulation coating layer was wrapped five times with a Teflon (trade name) sheet with a thickness of 0.1 mm. In the structure thus formed, no change in characteristics was observed even after 300 hours had passed, except for a slight electrolytic corrosion phenomenon at the ends of the external electrodes.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional example, and FIG. 2 is a sectional view showing an embodiment of this invention. 11... Straight pipe, 12a, 12b... Cylindrical body, 1
3a, 13b... Disc, 14... Insulating coating layer.

Claims (1)

[Scope of utility model registration request] A straight pipe made of quartz, a pair of cylindrical bodies partially connected to both ends of the straight pipe in a crowned state, a partition body provided integrally or airtightly connected inside these cylindrical bodies, and these negative and positive electrodes that airtightly penetrate the partition and are partially provided facing each other on both sides of the inside of the straight pipe; 1. A water-cooled discharge lamp comprising: an outer surface; and an insulating coating layer formed on the outer surface.