JPS6322694Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of an ion laser tube, and particularly to a structure for directly attaching a large number of heat sinks to a porcelain discharge channel thin tube (hereinafter referred to as a thin tube).

Some ion laser tubes, such as argon ion (Ar ⁺ ) laser tubes, have a thin tube portion formed of a porcelain material such as alumina or beryllia in order to ensure mechanical strength and heat resistance. This thin tube has an extremely small bend with respect to the central axis.
Moreover, it is necessary to have a uniform inner diameter dimension, and at the same time, since the thin tube is often part of an airtight envelope, dimensional processing accuracy is good, and it is possible to make an airtight bond with metal parts through metallization processing etc. A material made of alumina or beryllia porcelain is often used.

Laser tubes using other discharge channel materials include a large number of annular parts made of graphite or heat-resistant metals such as tungsten, molybdenum, etc., arranged coaxially and insulated from each other in a quartz glass envelope. There is something that made me

In such an argon ion laser tube, a relatively large current of several amperes to several tens of amperes flows through the discharge path, most of which is converted into heat and released outside the tube. Therefore, it is necessary to forcibly cool the laser tube, especially the discharge path, to prevent the laser tube itself from being destroyed by heat, and to take measures to prevent changes in the resonance conditions of the laser oscillator as much as possible. Ta. Incidentally, if such forced cooling is not performed, for example, in a laser tube using a beryllium porcelain capillary tube with an output of 0.1 W, the temperature at the capillary section will instantly rise to over 1000°C, and the porcelain capillary tube will suffer from thermal shock. Twist and destroy. That is, in argon ion laser tubes, the problem of cooling the discharge path forming material is extremely important for performance, and whether or not a stable cooling method is provided for a long period of time significantly affects the performance and life of the laser tube. It is no exaggeration to say that it determines the reliability of the entire laser-based device.

Conventionally, as a cooling method for a laser tube using a porcelain capillary, heat generated in the capillary is forcibly cooled using a fan or the like by attaching a heat radiator (radiator) closely fixed to the outer surface of the capillary. Although this method is relatively simple, it is virtually impossible to completely fix the heat sink to the surface of the thin tube, and it often loosens during use due to the difference in thermal expansion between the two. Insufficient cooling caused thermal shock cracks in the porcelain (tubes), overheating caused damage to the seals between the tubes and other metal parts, and cracking and melting of the brazing filler metal in brazing parts caused leaks. As one method to solve these problems, improvements have begun to be made in which the surface of the thin tube is metallized and a heat sink is joined to this directly or through other metal sealing parts by brazing or the like. .

FIG. 1 shows the structure of such a conventional ion laser tube, and the center part of the figure shows the mounting structure of the thin tube and the heat sink. Here, the outer surface of a thin tube 1 made of beryllia porcelain with high thermal conductivity is metallized (not shown), and a long cylindrical metal member 2 made of Kovar metal and an oxygen-free copper plate are formed in correspondence with the metallized surface. A disc-shaped heat dissipation plate 3 is brazed. The use of beryllia porcelain is necessary to improve the cooling effect due to its high thermal conductivity, but its mechanical strength is low compared to other porcelains, such as alumina porcelain. (approximately 1/2) For this reason, great care must be taken when designing the laser tube.
Due to the excessive stress generated due to the difference in thermal expansion characteristics between the cylindrical, i.e., metal member 2 and the heat sink 3, which are continuously wrapped and sealed around the outer periphery of the capillary, and the capillary, the beryllia capillary Sometimes it was destroyed. This has been one of the factors that lowers the manufacturing yield of laser tubes.

The present invention was proposed to solve these problems, and compared to conventional methods, it reduces the stress caused by brazing and makes it possible to braze the entire sealing part with a uniform thickness. The structure has been devised.

In other words, the brazing gap, which is the most important in brazing, can be optimized by dividing the metal member into multiple pieces and using weights to effectively act, while also reducing thermal expansion differences, thermal deformation of parts, and soldering. It is characterized by having a structure that can automatically correct gaps, etc. that occur as the materials melt, and by substantially reducing the dimensions of the sealed parts to reduce the absolute amount of stress due to expansion differences. It is.

The present invention will be explained in more detail below using examples.

FIG. 2 is a cross-sectional view (a plane perpendicular to the tube axis) of a narrow tube portion of an ion laser tube showing an embodiment of the present invention.

First, a beryllia porcelain thin tube 21 having an outer diameter of 16 mm, a length of 120 mm, and an inner diameter of 1.2 mm was prepared. Next, 6 mm from both ends of this magnetic capillary tube and 50 mm each from the center to both sides.
Metallization with M ₀ to Mn was applied to the outer surface of each mm (not shown). Meanwhile, thickness 0.6mm, inner diameter
Make a Kovar alloy cylinder of 16.05mm and 100mm length.
This metal member 22 is divided into two parts in the circumferential direction.
As shown in the figure, 25 sets (50 sheets) of heat dissipating plates 23 were prepared by punching an oxygen-free copper plate having a thickness of 1.5 mm into two circular circular shapes using a press die. In addition, as shown in FIG. 1, other parts include an enclosure dish 6 that connects the thin tube 1 and the cathode side glass bulb 5, and
An enclosure plate 7 for connecting the M ₀ anode 4 and the thin tube 1, and an enclosure plate 8 for connecting the anode 4 and the anode-side glass bulb 9 were prepared.

First, the thin tube 21, the anode 4, and the enclosure dishes 6, 7, 8
were brazed with BAu-1V solder (not shown). Note that the brazing temperature was 1040°C. Next, the assembly of the thin tubes 21 and the 50 heat sinks 23 are connected to the BAg-8 through the two divided cylindrical metal members 22, respectively.
Brazing was performed using wax (not shown). At this time, the brazing temperature was 830°C, and a weight of approximately 2.5 kg was used.

However, as shown in FIG. 2, the bonding positional relationship between the heat sink 23 and the metal member 22 is arranged such that the inner circumference of the heat sink 23, which is divided into two, substantially coincides with the outer circumference of the metal member 22. That is, one heat sink 23 is bonded only to one opposing metal member, and care is taken not to contact other divided metal members. By doing this, the inventor has confirmed that the following remarkable effects are achieved.

Even if there is some discrepancy between the outer diameter of the thin tube and the inner diameter or curvature of the metal member, it can be adjusted by making the weight for brazing sufficiently large. Also, the brazed gap can be adjusted appropriately using weights in the same way. That is,
By integrating and dividing the metal member 22 and the heat dissipation plate 23, it was possible to convert the cylindrical fitting type brazing structure to a so-called stacking type brazing structure, so that the brazing design and brazing The working conditions have become extremely simple and stable, and from an industrial perspective, mass productivity has significantly improved.

After the ion laser capillary assembly with the heat sink attached in this way, the cathode bulb 5 with the cathode 10 attached and the anode bulb 9 are attached using a glass lathe, and the gas return pipe 30 and pre-user face plate 12 are attached respectively. The installed ion laser encapsulated tube has been completed. This tube was evacuated, filled with gas, and dried through the same process as usual, resulting in an ion laser tube with laser light output as originally designed. However, compared to the conventional heat sink mounted with a cylindrical metal member, the effective area of brazing has been significantly increased, improving cooling efficiency by approximately 70% and reducing the time required for initial stabilization of the laser oscillator. In addition, various troublesome problems caused by heat could be solved. Furthermore, during the manufacturing process of the laser tube, there were no accidents caused by thermal shock, especially during exhaust and withering, confirming that this idea is extremely effective from an industrial perspective.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but includes all cases in which similarly divided heat sink groups are attached via metal members divided into porcelain thin tubes, and the method of division, It is clear from the above description that there is no limitation to the number, etc.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a conventional laser tube, and FIG. 2 is a cross-sectional view of the vicinity of the thin tube portion of an improved laser tube showing an embodiment of the present invention. Here, 1 and 21 are thin tubes, 2 and 22 are metal members, 3 and 23 are heat sinks, 4 is an anode, and 5
1 shows a cathode bulb, 6, 7, and 8 are enclosure plates, 9 is an anode bulb, 10 is a cathode, 30 is a gas return pipe, and 12 is a glass face plate.

Claims (1)

[Scope of utility model registration request] In an ion laser tube in which the discharge channel tube is made of a porcelain material, the outer circumferential surface of the discharge channel tube is metallized, and the metal member is divided into a plurality of pieces with respect to a cross section perpendicular to the tube axis of the discharge channel tube; 1. An ion laser comprising a heat sink divided into two parts corresponding to each of the metal members, wherein the discharge channel tube, the metal member, and the heat sink are integrated by brazing. tube.