JPH08181367A - Air cooled ion laser tube - Google Patents

Abstract

PURPOSE: To improve rise and stability of laser output, in an air cooled ion laser tube. CONSTITUTION: The density of slits of a heat sink 5a soldered to a ceramic thin tube 4 is made rough on the cathode 3 side wherein heating value is large and dense in accordance with the distance shorter form the anode 2 side wherein heating value is small as compared with the cathode 3 side. Thereby the temperature distribution of the ceramic thin tube 4 is made uniform, and rise and stability of the laser output are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-cooled ion laser tube, and more particularly to the structure of its heat sink.

[0002]

2. Description of the Related Art Ion laser tubes include air-cooled ion laser tubes and water-cooled ion laser tubes depending on the method of cooling a laser tube which is heated to a high temperature by heat generated when a gas is discharged and excited. The air-cooled in-on laser tube has a structure used for a laser having a relatively low output, and is widely used because it can be made small.

FIG. 6 (a) shows a cross-sectional view of the conventional air-cooled ion laser tube passing through the central axis, and FIG. 6 (b) shows a cross-sectional view of a heat radiating plate portion perpendicular to the central axis. As shown in FIG. 6, a conventional air-cooled in-on laser tube includes an envelope 1 enclosing a laser medium, an anode 2 and a cathode 3 which are electrodes for discharge-exciting the laser medium, an anode 2 and a cathode 3. A ceramic thin tube 4 between which the laser medium is excited and held in a discharge state, a plurality of radial plates are brazed to the outside of the thin tube 4 to radiate heat generated by the discharge, and an envelope. It is composed of a total reflection mirror 6 which is located at both ends of 1 and constitutes a resonator for taking out laser light from the excited laser medium, and an output mirror 7 which outputs laser light having a constant transmittance.

The heat dissipation plate 5 is made of a metal having a good thermal conductivity, for example, copper. However, since the ceramic thin tube 4 is made of ceramic, which is an insulating material, there is a problem that a ceramic crack occurs due to a difference in thermal expansion between the metal and the ceramic. there were. On the other hand, as shown in FIG. 6, the heat radiating plate 5 is divided into plural pieces in the tube axis direction and brazed to relax the stress caused by the difference in thermal expansion and prevent ceramic cracking.

Further, in Japanese Patent Laid-Open No. 2-47895, a high conductive metal heat sink plate is formed with slits for partitioning the mounting surface,
There is disclosed a technology of reducing the thermal stress due to the difference in thermal expansion from the ceramic circuit board to which the heat dissipation plate is attached and preventing the adhesion and peeling of the two.

Further, in Japanese Patent Laid-Open No. 60-175499, a radiation fin attached to an alumina substrate has a plurality of slits formed on an adhesive surface of the alumina substrate to prevent thermal stress due to a difference in thermal expansion between the alumina substrate and the radiation fin. Alleviate
A structure is disclosed that prevents warpage or cracking on the substrate.

In Japanese Utility Model Laid-Open No. 62-51754, a zigzag folded fin is inserted into a slit formed at regular intervals in a metal base on which a heat-generating component is attached, and the fin is fixed by a repulsive force generated by a difference in thermal expansion. Techniques for doing so are disclosed.

[0008]

In this conventional air-cooled ion laser tube, the heat dissipation plate has a uniform shape over the entire ceramic capillary tube. On the other hand, the amount of heat generated from the ceramic capillary varies depending on the location of the capillary. For this reason, the temperature distribution of the ceramic cannot be made uniform by cooling with a heat dissipation plate having a uniform shape, and as a result, stress is generated in the ceramic, which causes twisting of the thin tube and misalignment of the mirror. Therefore, it is difficult to improve the rise of the laser output and the stability characteristics.

[0009]

An air-cooled in-on laser tube according to the present invention comprises a gas as a laser medium, an anode and a cathode as discharge electrodes, and an anode and a cathode located between the anode and the cathode. A ceramic thin tube portion where the laser medium is excited and held in a discharge state, a heat radiating plate which is brazed to the outside of the ceramic thin tube and radiates heat generated during discharge, and the excited laser medium located at both ends of the envelope An air-cooled ion laser tube comprising a total reflection mirror that constitutes a resonator for extracting laser light from an output mirror and an output mirror having a constant transmittance. The brazing surface of the thin tube is provided with a plurality of slits at irregular intervals. Further, the heat radiating plate is provided with a plurality of slits having different widths on the brazing surface so that the temperature distribution of the ceramic thin tube becomes uniform. Further, the heat radiating plate is provided with a plurality of slits having different depths on the brazing surface of the ceramic thin tube so that the temperature distribution of the thin tube becomes uniform. Further, in the heat dissipation plate, the plurality of slits have a constant shape and a constant pitch so that the temperature distribution of the thin tubes becomes uniform, and the area becomes smaller from the cathode to the anode. Also,
In the heat dissipation plate, the plurality of slits have a constant shape and a constant pitch so that the temperature distribution of the thin tubes becomes uniform, and the thickness decreases from the cathode to the anode.

[0010]

The present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of the present invention.
1A is a cross-sectional view of the air-cooled ion laser tube passing through the central axis, and FIG. 1B is a cross-sectional view of a heat dissipation plate portion perpendicular to the central axis. The laser medium enclosed in the envelope 1 is the anode 2
Heat is excited between the cathode 3 and the cathode 3, and the obtained light resonates by the optical resonator composed of the total reflection mirror 6 and the output mirror 7, and a part of the resonated light passes through the output mirror 7 to cause laser light. Output as light. At this time, the ceramic thin tube 4
Since the inside of the tube is in a discharged state and a plurality of heat radiating plates 5a for cooling are attached in the radial direction to the outside of the thin tube 4 to generate heat, heat is radiated. Here, the heat dissipation plate 5a is provided with a plurality of slits 8, and the density of the slits on the cathode 3 side, which has a large amount of heat generation, is made sparse to increase the amount of heat dissipation, and as the amount of heat generation becomes smaller, it approaches the anode 2 side. The shape is made dense so that the amount of heat radiation is limited and the temperature of the ceramic thin tube is made uniform.

FIG. 2 is a diagram showing a second embodiment of the present invention.
FIG. 2A is a cross-sectional view through the center axis of the air-cooled ion laser tube, and FIG. 2B is a cross-sectional view of a heat dissipation plate portion perpendicular to the center axis. In this embodiment, as shown in FIG.
By making the width of the slit 8 on the side of the cathode 3 having a large heat generation smaller than that on the side of the anode 2, the temperature of the ceramic thin tube is made uniform.

FIG. 3 is a diagram showing a third embodiment of the present invention.
FIG. 3A is a cross-sectional view through the center axis of the air-cooled ion laser tube, and FIG. 3B is a cross-sectional view of a heat dissipation plate portion perpendicular to the center axis. In this embodiment, as shown in FIG.
By making the depth of the slit 8 on the cathode 3 side, which has a large amount of heat generation, smaller than that on the anode 2 side, the temperature of the ceramic thin tube is made uniform.

FIG. 4 is a diagram showing a fourth embodiment of the present invention.
FIG. 4A is a cross-sectional view through the center axis of the air-cooled ion laser tube, and FIG. 4B is a cross-sectional view of a heat dissipation plate portion perpendicular to the center axis. In this embodiment, as shown in the figure, in the heat dissipation plate 5d, each of the plurality of slits 8 has a constant shape and a constant pitch so that the temperature distribution of the thin tubes is uniform, and the area is from the cathode 3 to the anode 2. It is getting smaller.

FIG. 5 is a diagram showing a fifth embodiment of the present invention.
5 (a) is a cross-sectional view through the center axis of the air-cooled in-on laser tube, FIG. 5 (b) is a cross-sectional view of the cathode side heat sink plate perpendicular to the center axis, and FIG. 5 (c) is the center. FIG. 6 is a cross-sectional view of a portion of a heat dissipation plate on the anode side perpendicular to the axis. In this embodiment, the heat radiating plate 5e has a plurality of slits 8 having a constant shape and a constant pitch so that the temperature portion of the thin tube is uniform, and the thickness decreases from the cathode 3 to the anode 2.

Further, any combination of the above embodiments can be used. The density, width, and depth of the slits are determined so that the temperature distribution of the ceramic thin tube is uniform.

[0016]

As described above, according to the present invention, the structure of the heat dissipation plate of the air-cooled ion laser tube is devised so that the temperature distribution of the ceramic thin tube becomes uniform, so that the laser output rises and stabilizes at the start. The result is that the degree characteristics are improved.

[Brief description of drawings]

1A is a sectional view of an air-cooled in-on laser tube showing a first embodiment of the present invention, and FIG. 1B is a sectional view of a heat radiating plate portion.

2A is a cross-sectional view of an air-cooled ion laser tube showing a second embodiment of the present invention, and FIG. 2B is a cross-sectional view of a heat dissipation plate portion.

FIG. 3A is a sectional view of an air-cooled ion laser tube showing a third embodiment of the present invention, and FIG. 3B is a sectional view of a heat radiating plate portion.

4A is a sectional view of an air-cooled ion laser tube showing a fourth embodiment of the present invention, and FIG. 4B is a sectional view of a heat radiating plate portion.

5A is a sectional view of an air-cooled ion laser tube showing a fifth embodiment of the present invention, and FIGS. 5B and 5C are sectional views of a heat radiating plate portion.

6A is a cross-sectional view of an air-cooled ion laser tube according to a conventional technique, and FIG. 6B is a cross-sectional view of a heat dissipation plate portion.

[Explanation of symbols]

 1 Enclosure 2 Anode 3 Cathode 4 Ceramic Capillary Tube 5, 5a to 5e Heat Dissipator 6 Total Reflection Mirror 7 Output Mirror 8 Slit

Claims (4)

[Claims] 1. A gas which is a laser medium, an anode and a cathode which are discharge electrodes, a ceramic thin tube portion located between the anode and the cathode, in which the laser medium is in a discharge state, and the ceramic thin tube. A plurality of heat dissipation plates that are brazed to the part to dissipate the heat generated during discharge, a total reflection mirror that forms a resonator that extracts laser light from the laser medium that is positioned at both ends of the envelope and is excited by discharge, and part In the air-cooled ion laser tube having an output mirror for transmitting the light, the heat dissipation plate is brazed to the ceramic thin tube in the radial direction so that the heat capacity decreases from the cathode side to the anode side. An air-cooled ion laser tube characterized in that 2. The air-cooled ion laser tube according to claim 1, wherein the heat radiating plate has a plurality of slits on the brazing surface of the ceramic thin tube at unequal intervals. 3. The air-cooled ion laser tube according to claim 1, wherein the heat dissipation plate has a plurality of slits having different widths on a brazing surface of the ceramic thin tube. 4. The air-cooled ion laser tube according to claim 1, wherein the heat dissipation plate has a plurality of slits having different depths on a brazing surface of the thin tube.