JPS5974691A - Cross flow type gas laser device - Google Patents

Abstract

PURPOSE:To efficiently obtain a high output laser beam at a low cost from a cross flow type laser device by using a three phase AC power source for discharge. CONSTITUTION:When the output voltage of the three phase power source 10 is impressed on electrodes 13a-13d, discharge regions 15a-15c are formed between the electrodes by gas flows 14. Laser oscillation is performed by a resonator consisting of mirrors 16-21, and the beam 22 is taken out through the mirror 21. If the discharge starting voltage is less than 40-50% of the source voltage (peak value), there is no substantialy differnce between the case of the three phase AC power source and that of a DC power source. When a gas pressure, voltages between the electrodes, and an injected power are put in the same conditions, the three phase AC power source can be miniaturized by the reduction of an electrode length. Besides, the efficiency can be increased to 97% or more, and the manufacturing and operating costs reduce.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called cross-flow type laser device in which the discharge direction, gas flow direction, and optical axis direction are orthogonal to each other.

This type of conventional gas laser device uses an expensive and low-efficiency DC power source or high-frequency power source as a discharge power source, and therefore cannot produce a single output laser beam at a low cost.

As shown in Fig. 1, the DC power supply described above includes a circuit 1 for power control of three-phase AC (a power control circuit using Cyrisk), a transformer 2 for boosting the output of this control circuit 1, and a transformer 2 for boosting the output of this control circuit 1. It consists of a rectifying circuit 3 and a smoothing circuit 4 which sequentially convert and smooth the secondary output of the circuit. The high-frequency power source also includes a circuit 5 for converting three-phase alternating current into direct current, a circuit 6 for smoothing the output of the circuit 5, an inverter circuit 7 for converting the output of the smoothing circuit 6 into high-frequency power, and this inverter circuit. The transformer 8 boosts the output of the transformer 7.

In view of the above-mentioned drawbacks of the conventional laser device, an object of the present invention is to
An object of the present invention is to provide a cross-flow type gas laser device that can obtain high-output laser light at low cost. Therefore, in the present invention, a three-phase cross-current power source is used as the power source for the discharge turtle.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 3 shows a power supply used in the cross-flow type gas laser device according to the present invention, and this power supply 10 includes a circuit 11 (automatic pressure regulator AVR) for controlling the power of the front three-phase AC,
It consists of a transformer 12 that boosts the output of this power control circuit 11 to KV order.

FIG. 4 shows how the discharge electrodes 13a, 13b, 13c, and 13d arranged in parallel at predetermined intervals in the vertical direction are connected to the power source 10, and FIG.
The equivalent connection diagram of the load impedance and the above-mentioned power supply 10 is shown in the case where the load impedance between the electrodes 13b and 130 is set to be the same as that between the electrodes 13c and 13d.

Note that r shown in FIG. 5 is a stabilizing resistor.

Now, when the output voltage of the power supply 10 is applied to the electrodes 13a-13d in the manner shown in FIG. 4, a discharge as shown in FIG. 6 occurs between the electrodes under the influence of the gas flow 14 made of the laser material. Regions 15a, 15b and 15c are formed. However, the rear mirror 16, folding mirrors 17, 18
．． Laser oscillation is performed by a resonator consisting of 19, 20 and an output mirror 21, and a laser beam 22 is extracted via the output mirror 21.

Figures 7 and 8 show the instantaneous power consumption when a DC power source and a single-phase AC power source are respectively connected between the discharge electrodes with a pure load connected between the discharge electrodes, and Figure 9 shows the instantaneous power consumption when a pure load is connected between the discharge electrodes. The figure shows the instantaneous power consumption when the loads "@b t rbe" and "red" are pure loads.
In the figure, the reason why the cardiac force is constant is because there is a connection between the individual electrodes mentioned above. The power consumed by the load rA, J′ Wab −
This is because W- and Wca are added together.

Next, considering the case where the load is not a pure load but a discharge "L negative," the DC', υ, and the respective discharge instants when using a single-phase AC L power source and a three-phase father current source 10 are as follows. The power consumption is shown in Figure 10, i% Figure 11, and Figure 12, respectively.In other words, when four DC sources are used, the power consumption is constant, or when a single-phase AC υIC power source is used, the discharge starts. The discharge stops when the pressure is lower than the heavy pressure, so that the laser light is intermittent at a frequency (100 Hz or 120 Hz) that is twice the operating frequency i (50 Hz or 60 Hz).

On the other hand, when the three-phase alternating current source 10 is used, the mental force obtained by superimposing the voltages shown in FIG. 11 by shifting them by 120 degrees will be consumed. or 7>, use a frequency 6 times the above commercial frequency (300Hz or 360Hz).
z) Already there is a ripple in the force, but this ripple can be practically ignored by setting the power supply voltage sufficiently higher than the discharge start voltage.

That is, FIG. 13 shows the calculated relationship between the discharge starting voltage and the discharge power ripple in the example shown in FIG. As is clear from the calculated figure 14, the discharge starting voltage is 40% of the power supply voltage (peak value).
In a state of ~50% or less, there is no substantial difference between the case where a three-phase AC power source is used and the case where a DC power source is used.

Next, it will be explained that the laser device of the present invention using a three-phase AC power source can have a smaller discharge section than the laser device using a DC power source.

An important point in realizing a small, high-output laser device is to increase the discharge power density (W/σ2), but if the voltage between the electrodes is increased for this purpose, an arc will occur and the discharge will stop. . Therefore, there is a limit to the discharge power density, which is determined by the ratio of electric field strength to gas pressure (E/P).

Now, if we compare the electrode shapes when using a three-phase AC d source and when using a DC power source, under the conditions that the same injection force is obtained with the same gas pressure and the same interelectrode voltage,
As shown in FIG. 15, when a DC power source is used, the electrode length is twice as long as when the three-phase AC power source is fully used. Therefore, if a three-phase AC power source is used, there is an advantage that the laser device can be made smaller.

In the case of a 1kW class laser device, the electrode length L1 and the electrode arrangement interval d shown in FIG.
~5crn8, and the layer thickness t of the discharge part is '-1' is 2.
~3Crn.

In the above embodiment, four rod-shaped electrodes i3a to 14& are used, but in order to prevent arc transition, these electrodes are replaced with fraction 1 type electrodes 13a' as shown in FIG.
..., 13 t..., 13 c'...
. , 13d'... may be used, and each of these electrodes may be connected to the three-phase AC power source 1 through a stabilizing resistor r.

The cross-flow type gas laser device according to the present invention, which uses a three-phase AC power source as a power source for emission, has the following effects.

■ As is clear from the comparison of Figures 1, 2, and 3, the configuration of the power source for the release is extremely simple, so the equipment cost can be reduced by one inch, and the operating cost is that much lower than the conventional equipment. Note that in this type of laser device, the discharge power source occupies a large proportion of the device cost.

■ The efficiency of a DC power supply is around 90% and that of a high frequency power supply is around 70%, while that of a 3-phase AC power supply is 97%.
% or more, therefore, it is advantageous when obtaining a high output laser beam.

■ The discharge section can be made smaller than when using a DC power supply.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing configuration examples of a DC power source and a high frequency power source, respectively. FIG. 3 is a block diagram showing a configuration of a three-phase AC power source used in a radar device according to the present invention. Figure 4 is a perspective view conceptually showing the arrangement of each discharge electrode and the mirrors constituting the resonator, and the connection between the electrodes and a three-phase AC power supply, and Figure 5 is a diagram showing each discharge electrode and three-phase AC power supply. Fig. 6 is a conceptual diagram showing the mode of discharge, Fig. 7, Fig. 8, and Fig. 9 show the instantaneous consumption when using a DC power supply with a pure load interposed between the two. Graphs showing instantaneous power consumption when using single-phase AC power supply and instantaneous power consumption when using three-phase AC power supply, respectively. Figures 10, 11, and 12 show instantaneous power consumption when using DC power supply during discharge load. Figure 13 is a graph showing the instantaneous power consumption when using a single-phase AC power supply and the instantaneous power consumption when using a three-phase AC power supply. Figure 14 is a graph showing the efficiency of power injected into the discharge section, and Figure 15 shows a comparison of the electrode shape when using a three-phase AC power source and the electrode shape when using a DC power source. FIG. 16 is a conceptual diagram showing another example of the configuration of the discharge electrode. 10... Three-phase AC power supply, 11... Power control circuit, 1
2... Step-up transformer, 13a-13d... Discharge electrode, 14... Gas flow, 16... Rear mirror, 17-2
o... Reflection mirror, 22... Redebeam, 13
a' to 13d'...divided discharge electrodes. Figure 4 Figure 6 Figure 7 Figure 10 Figure 8 Figure 11

Claims (1)

[Claims] A cross-flow type gas laser device characterized in that a three-phase AC power source is used as a discharge power source.