JPH01214183A - Gas laser oscillation device - Google Patents

Abstract

PURPOSE:To suppress fluctuation of laser output and to improve efficiency by setting the neighboring two out of discharge tubes which are divided into an even number, by enabling laser gas to flow from both edges of the two discharge tubes toward the center, and by enabling laser gas to be discharged in the direction of diameter from a diffuser provided at the center. CONSTITUTION:A discharge tube is divided into two in this case and is installed on the laser optical axis. A discharge box 7 is provided between these two discharge tubes 1 and a discharge duct 7a, disc-like diffuser 7c, and a circular gas-collecting tube 7d are installed at a box 7. Mirror boxes 5 and 6 are installed at the outer edge of the discharge tube 1. Laser gas flows into boxes 5 and 6 from discharge pipes 5a and 6a and the flow is controlled at gas reservoirs 5b and 6b. Then, laser gas is supplied from the boxes 5 and 6 to the discharge tube 1 which is divided into 2. And gas within the discharge tube 1 is excited by discharged caused by an electrode 2. Laser gas heated by discharge is collected at the box 7 and is discharged through the disc-shaped diffuser 7c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a high-output gas laser oscillation device used for, for example, laser welding or laser cutting.

(Prior Art) FIG. 6 shows a conventional gas laser oscillation device disclosed in, for example, Japanese Patent Laid-Open No. 62-200780. A laser gas is sealed inside the oscillation device, and the laser gas is circulated by a blower 10. Laser gas from the blower 10 passes through a heat exchanger 12, is accelerated by a reducer 13, and flows into the discharge tube 1. The laser gas that has passed through the discharge tube is decelerated by the diffuser 14 and returns to the reblower through the heat exchanger 11. Two electrodes 2 are installed on the outside of the discharge tube 1 so as to face each other in a direction perpendicular to the direction in which the laser gas passes. A high-frequency AC voltage is applied between the two electrodes 2, and a discharge is caused inside the discharge tube 1. This discharge excites the laser gas flowing through the discharge tube 1, and the laser beam is extracted by the reflecting mirrors 3 and 4. Heat exchangers 11 and 12 are provided before and after the discharge tube 1. The heat exchanger 11 is provided to cool the laser gas heated to a high temperature by discharge, and the heat exchanger 12 is provided to cool the gas heated by the blower.

(Problem to be Solved by the Invention) In a conventional laser oscillation device, the angle of the diffuser 14 was set at around 10°. This is because if the diffuser is suddenly expanded, the laser output will fluctuate, which will have an adverse effect on laser processing. Fluctuations in laser output cause defects such as poor melting in laser welding and rough cut surfaces in laser cutting. On the other hand, when the angle of the diffuser 14 is small, around 10 degrees, the length of the diffuser becomes longer than when it is suddenly expanded. While laser gas emits laser light, it also absorbs it. The rate of absorption increases as the temperature of the laser gas increases, and decreases as the temperature decreases, so if the diffuser through which the high-temperature laser gas flows in the discharge tube is long, the laser light will be absorbed in this portion, worsening laser efficiency. If the length of the diffuser with an angle of 10'' is shortened in order to prevent deterioration of laser efficiency, it becomes difficult for the laser gas to flow, and the power required to flow the gas increases.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to obtain a gas laser oscillation device that suppresses fluctuations in laser output and improves oscillation efficiency.

[Structure of the Invention] (Means for Solving the Problem) A discharge tube is divided into an even number of parts, two of which are adjacent to each other as a set, and laser gas is flowed from both ends of the two towards the center of the two. A disc-shaped diffuser is provided in the center of the discharge tube, and the laser gas is discharged in the radial direction of the discharge tube.

Each discharge tube undergoes discharge excitation to extract laser light.

(Function) According to the present invention, it is possible to obtain a laser oscillation device in which the efficiency of the oscillation device is less reduced due to absorption of laser light by laser gas and the laser output is less fluctuated.

(Example) Fig. 1 shows a discharge 4vt1 laser oscillation device of the present invention.
is divided into two parts and placed on the laser optical axis.

An exhaust box 7 is installed between the two discharge tubes 1.

The exhaust box 7 is equipped with an exhaust duct 7a, a disc-shaped diffuser 701, and an annular air collection pipe 7d. 2
The other end of the book discharge tube 1 has a mirror box 5, respectively.
, 6 are attached. A reflecting mirror 3, a semi-transparent mirror 4, and gas supply pipes 5a and 6a are attached to each mirror box, respectively.

Furthermore, each mirror box has a gas reservoir 5b.

6b is provided.

The laser gas is supplied to the mirror boxes 5 and 6 through air supply pipes 5a.

6a, and are once rectified by gas reservoirs 5b and 6b. Laser gas is supplied to the two-divided discharge tube 1 from mirror boxes 5 and 6. The gas inside the discharge tube is excited by the electrical discharge caused by the electrodes 2. Laser gas heated by the discharge is collected in an exhaust box and discharged through a diffuser 70 having a disc-shaped flow path.

In this embodiment, the high-temperature laser gas that absorbs the laser beam is quickly discharged from above the laser optical axis because the diffuser is shaped like a disk. In this structure, the high-temperature laser gas is immediately discharged in the radial direction after exiting the discharge tube 1, so there is no part where the high-temperature gas accumulates like the space 16 in FIG. 6 of the conventional example. There is no possibility that the relay laser output will fluctuate due to absorption of light, which deteriorates the efficiency of the laser device. This is due to the following reasons.

In a laser gas, the higher the temperature, the higher the absorption rate of the laser beam, so when the gas absorbs the laser beam, the temperature and absorption rate of the gas increase simultaneously. In this example, the laser gas, which has become hot due to discharge, is exposed to the laser beam. Since the time is short, absorption of the laser light does not cause the gas temperature to rise and the absorption rate becomes higher and higher, and the distance exposed to the laser light is also short, so light absorption can be kept to a minimum. Furthermore, if the gas flow is disturbed in the space 16 of the prior art example shown in FIG. 6, where the gas temperature is high, there are moments when a region of very high temperature locally occurs due to the absorption of laser light. That is, some gases are exposed to the laser beam for a long time and others are not exposed to the laser beam for a long time, and this is caused by the flow disturbance. The gas temperature distribution therefore constantly fluctuates. At this time, since the laser light is absorbed in the high temperature part, fluctuations occur in the laser output.

This does not happen in this embodiment. This was also confirmed experimentally. In addition, the gas flow is once decelerated in the mirror box and the turbulent energy and blower pressure pulsations are dissipated before being guided to the discharge tube, so there is less turbulence in the flow of the discharge tube, which is the cause of output fluctuations inside the discharge tube. There will be no non-uniformity and fluctuations in the gas.

Furthermore, since high-temperature laser gas is not blown onto the reflector, the reflector is protected from dust and ions generated by discharge on the surface of the reflector, resulting in a longer service life.

When this example was applied to an output IKV carbon dioxide laser, the laser efficiency improved by about 0.5%, and the output fluctuation was reduced by 2%.
It showed a good value within (p-p value/output).

The third box in FIG. 2 shows another example of the shape of the exhaust box 7.

In the example shown in FIG. 2, the disc-shaped diffuser 7c has a narrow width on the outer diameter side. As shown in the figure, when this angle is around 20 degrees, the flow loss is minimized. FIG. 3 is a sectional view of the diffuser viewed from the axial direction of the discharge tube. The width of the diffuser is kept constant as in Figure 1, and wedges 7e and 7f are attached instead to reduce the flow loss.

FIG. 4 shows another embodiment according to the present invention. In this example 2
In order to stabilize the balance of the gas flow rate in the discharge tube 1, a throttle 8 is installed at the entrance of the mirror boxes 5 and 6.

If no throttle is provided in this part, the length, thickness, etc. of the piping from the blower to the two mirror boxes 5 and 6 must be the same, otherwise an imbalance in gas flow rate between the discharge tubes 1 may occur. be. By attaching a throttle to the mirror box 5.6, it is possible to balance the gas flow rate and to reduce the propagation of pressure pulsations generated from the blower to the discharge tube.

FIG. 5 shows yet another embodiment of the present invention.

In this example, there are four discharge tubes 1, and gas is supplied from an air supply box 9 to the two central discharge tubes.

By adopting such a configuration, any number of discharge tubes can be connected, so that a laser oscillation device with high output, high efficiency, and small output fluctuation can be easily provided.

〔Effect of the invention〕

As described above, according to the present invention, a discharge tube is divided into an even number, two of which are adjacent to each other are set as a set, and laser gas is flowed from both ends of the two toward the center of the two discharge tubes. Since a disc-shaped diffuser is provided in the center of the discharge tube and the laser gas is discharged in the radial direction of the discharge tube, fluctuations in laser output can be suppressed and a gas laser oscillation device with improved efficiency can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a laser oscillation device of the present invention, FIGS. 2 and 3 are sectional views showing an exhaust box of the device of the present invention, and FIGS. 4 and 5 are sectional views showing other embodiments of the present invention. Sectional view shown, No. 6
The figure is a sectional view showing a conventional laser oscillation device. 1...Discharge tube 2...Electrode 3...Reflector 4...Semi-transparent mirror 5.6...Mirror box 7...Exhaust box 8...Aperture 9...Air supply box lO...Blower 11, 12...Heat exchanger 13...Reducer 14...Diffuser agent Patent attorney Nori Chika Nori Sokuma Daishimaru Kenko Ku

Claims (1)

[Claims] The discharge tube is divided into an even number, two of which are adjacent to each other as a set, and the laser gas is flowed from both ends of the two toward the center of the two, and a disk-shaped diffuser is installed in the center of the two discharge tubes. A gas laser oscillation device characterized in that a laser gas is discharged in a radial direction of a discharge tube.