JPH07105543B2 - Gas laser tube device - Google Patents

Description

The present invention relates to a gas laser tube apparatus, and more particularly to a forced air cooling type gas laser tube apparatus.

(Prior Art) In general, a gas laser tube device which fills a rare gas such as argon or krypton and causes a discharge to generate a laser beam has a feature that a relatively large output laser beam can be obtained in a visible region. For this reason, a large amount of power is consumed in the discharge thin tube part, so in order to improve heat dissipation, for example, beryllia porcelain, which has good thermal conductivity, is used for the discharge thin tube, and a plurality of heat dissipation plates made of copper or aluminum are used on the outer peripheral part. A heat transfer fixed structure is adopted. Then, a cooling fan blows cooling air between the heat radiating plates or sucks cooling air to forcibly cool it.

A conventional gas laser tube device of this type has a structure shown in FIGS. 8 to 10. In the figure, reference numeral 11 is a gas laser tube,
12 is a box-shaped laser tube housing case, 13 is a blower fan provided on the upper part of the case, 14 is a discharge tube of the laser tube, 15
Is a cathode part, 16 is an anode part, 17 and 18 are end tube parts extended on both sides thereof, 19 and 20 are a pair of laser mirror parts airtightly joined to their tip parts, and 21 is a plurality of rectangular plates. Heat sink, 22
Is a bottom base of the case, 23 and 24 are intake holes formed on both sides thereof, 25 is an upper cover, and 26 is an exhaust hole formed in the center thereof.

(Problems to be Solved by the Invention) When an apparatus having such a structure is operated, even if a configuration in which vibration is not transmitted from the blower fan to the laser tube is applied, it takes about several minutes from the start of laser oscillation. It was confirmed that the direction of the laser beam changes finely and in a very fast oscillatory mode. That is, in this conventional structure, as shown in FIG. 7, the emission direction of the laser beam is stable, and the laser beam is deviated by about 100 μrad. (Microradian) immediately after the oscillation. There is a slight change in direction. This minute directional fluctuation has a fluctuation width of several μrad. And a repetition frequency of several Hz (hertz).

The main reason for this is that, as schematically shown in FIG. 11, a part Fx of the cooling air F becomes a turbulent turbulent flow downstream of the discharge thin tube portion, vibrating the heat dissipation plate, and the vibration causes the laser beam to oscillate. It is thought that the direction of is changed minutely.

The present invention provides a gas laser tube device which can solve the above-mentioned inconveniences and can control a minute directional fluctuation of a laser beam.

[Structure of the Invention] (Means for Solving the Problems) The present invention relates to a plurality of heat dissipation plates that are fixed to the outer periphery of a discharge capillary by heat transfer and through holes that are ventilated to the leeward side of the discharge capillary. Is a gas laser tube device in which

(Operation) According to the present invention, the generation of turbulence in the downstream of the narrow discharge tube portion is alleviated, the vibration of the heat sink is suppressed, and thus the minute directional fluctuation of the laser beam is suppressed.

(Example) Hereinafter, an example will be described with reference to the drawings. The same parts are represented by the same symbols.

The embodiment shown in FIG. 1 to FIG. 3 has the following structure when only its characteristic part is explained. That is, in the plurality of heat dissipation plates 31 that are thermally conductively fixed to the outer periphery of the discharge thin tube portion, the upper side 23 of both side portions is bent to form the side blocking wall 32, and the laser is formed so that they closely contact each other. It is heat-conductively laminated and fixed to the outer periphery of the discharge thin tube portion of the tube. Each heat dissipation plate 31 has a discharge capillary fitting hole 33 formed at a position closer to the upstream side of the flow of cooling air than the center. That is, in FIG.
The upstream dimension L1 is shorter than the downstream dimension L2. Then, through holes 34 are formed on the downstream side of the discharge capillary fitting holes 33, respectively. The through hole 34 is formed at a position corresponding to a dimension L3 which is a half or more of the dimension L2 from the discharge capillary fitting hole 33, and the diameter thereof is set to be equal to or slightly smaller than the discharge capillary fitting hole 33. Is preferred.

Alternatively, as shown in FIG. 4, an oval through hole 34 may be used. Alternatively, as shown in FIG. 5, a slit-shaped hole 34 continuous to the downstream end of the heat sink may be used.

The flow of the cooling air by the blower fan 13 is indicated by the dotted arrow F.
As described above, the bottom of the case is generally sucked from the bottom, passes between the heat radiating plates, flows upward, and is discharged. Further, the side blocking walls 32 formed on both sides of the heat radiating plate have a function of flowing cooling air as an upward laminar flow, but are not essential.

According to the laser tube device of the present invention, as shown in FIG. 6, the variation in the radiation direction of the laser beam from the initial stage of oscillation to the stable state is at most about 60 μrad. Decreased to.

[Effects of the Invention] As described above, according to the present invention, it is possible to suppress the generation of turbulent flow of cooling air on the downstream side of the heat sink with a relatively simple structure, and shift the natural vibration frequency of the heat sink itself. Therefore, it is possible to effectively suppress the initial stage of oscillation of the laser beam and minute changes in direction.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a perspective view of a main part thereof, FIG. 3 is a side view of the main part, and FIGS. 4 and 5 are other views of the present invention. FIG. 6 is a characteristic view of a main part showing an embodiment, FIG. 7 is a characteristic view of the same, FIG. 7 is a characteristic view of a conventional structure, and FIGS. 8 and 9 are cross-sectional views showing a conventional structure and perspective views of the main part. FIG. 10 is a longitudinal sectional view of the main part, and FIG. 11 is a horizontal sectional view of the main part. 11 …… Gas laser tube, 12 …… Housing case, 13 …… Blower fan, 31 …… Heat radiation plate, 34 …… Through hole.

Claims (1)

[Claims] 1. A gas laser tube comprising a plurality of heat dissipation plates thermally fixed to the outer periphery of a discharge thin tube, a housing case for housing the laser tube, and a blower fan fixed to the housing case. The gas laser tube apparatus according to claim 1, wherein a through hole is formed on the leeward side of the discharge thin tube of each of the heat dissipation plates to allow ventilation.