JPH0832157A - Gas laser device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of such a case that the output of a gas laser device drops even when the discharging electrode pair of the laser device is divided into a plurality of pairs by suppressing electrical interference between each electrode pair. CONSTITUTION:A discharging space 14 is formed between high-voltage side electrodes 11 and 12 and a low-voltage side electrode 13. The terminals 11c and 12c installed to the electrodes 11 and 12 are axisymmetrically counterposed to each other with respect to the gap between the electrodes 11 and 12 near the gap. A phase synchronizing circuit 20 for synchronizing the phases of electric power supplied to the electrodes 11 and 12 is provided between the terminals 11c and 12c and high-frequency power amplifiers 18 and 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas laser device which oscillates laser light by applying a high frequency voltage between electrodes to cause discharge.

[0002]

2. Description of the Related Art FIG. 3 shows a vertical sectional structure of a general gas laser device. In FIG. 3, a metallic internal wind tunnel 2 having a U-shaped cross section is provided in an external wind tunnel 1 having a rectangular cross section. A flat plate-shaped first dielectric body 3a is airtightly attached to the center of the upper surface of the outer wind tunnel 1 side, and a flat plate-shaped second dielectric member 3a is formed on the inner wind tunnel 2 side so as to close the upper opening portion thereof. The dielectric 3b is attached in an airtight manner, and the discharge space 5 having a predetermined gap exists between the dielectrics 3a and 3b. Further, the high voltage side electrode 4a is attached to the center of the upper surface of the first dielectric 3a, and the low voltage side electrode 4b is attached to the center of the lower surface of the second dielectric 3b.
Is provided, and a high-frequency voltage is applied from the AC power supply 6 between the electrodes 4a and 4b.

Laser gas is sealed in a space between the outer wind tunnel 1 and the inner wind tunnel 2 at a pressure of about 60 Torr, and the inside of the inner wind tunnel 2 is communicated with the outside air. A blower 7 for circulating the laser gas in the direction of arrow A and a heat exchanger 8 for cooling the laser gas after flowing through the discharge space 5 are arranged in the lower part of the external wind tunnel 1.

In the gas laser device having such a structure, when a high frequency voltage is applied from the AC power source 6 between the electrodes 4a and 4b, the first dielectric 3a and the second dielectric 3b are formed.
An alternating current discharge is generated in the discharge space 5 via the laser beam, the laser gas flowing in the discharge space 5 is excited, and the laser light 9 is generated in the direction orthogonal to the paper surface.

[0005]

By the way, in order to realize a high power gas laser device of KW class or higher, it is necessary to increase the output of the AC power supply 6 for supplying high frequency power. In this case, the AC power supply 6 is generally configured by using semiconductor elements, but because of the limitation of the current capacity of the semiconductor elements, it is said that power is combined using a large number of semiconductor elements. It requires a circuit configuration. However, in such a configuration, there is a problem that the above-described loss in power combining increases. Therefore, conventionally, when the laser output is set to a large value, the electrode pair is divided into a plurality of pieces, and a plurality of AC power supplies for applying high-frequency power to each divided electrode pair are provided. That is, in the case of the example shown in FIG.
A configuration in which a is divided into a plurality of parts in the paper surface direction and a plurality of alternating-current power supplies for supplying high-frequency power to each divided electrode is adopted.

However, in the case of such a configuration, the phase of the voltage applied to each electrode pair may deviate in the portions close to each other between the adjacent electrode pairs. When such a phenomenon occurs, a standing wave is generated according to the electrical interference between the two, and therefore the potential distribution on the electrode becomes non-uniform and the laser output decreases. It causes problems.

The present invention has been made in view of the above circumstances, and an object thereof is to suppress electric interference between the electrode pairs even when the electrode pair for discharge is divided into a plurality of laser outputs. It is an object of the present invention to provide a gas laser device capable of preventing a situation where the power consumption is lowered.

[0008]

In order to achieve the above object, the present invention comprises a plurality of pairs of high-voltage side electrodes and low-voltage side electrodes which are arranged in a state of being opposed to each other with a discharge space filled with laser gas interposed therebetween. In a gas laser device adapted to apply a high-frequency voltage from an AC power supply between a high-voltage side electrode and a low-voltage side electrode, in a power supply path by the AC power supply, a power supply to each pair of the high-voltage side electrode and the low-voltage side electrode The configuration is such that phase synchronization means for matching the phases is provided (Claim 1).

In this case, the feeding points for the plurality of high-voltage electrodes can be arranged in line symmetry between the adjacent high-voltage electrodes (claim 2).

Further, the feed points having the above-mentioned line-symmetrical arrangement may be arranged in the vicinity of adjacent portions of each high voltage side electrode so as to face each other (claim 3).

Further, a distributed constant circuit may be provided between the high voltage side electrode and the low voltage side electrode forming a pair so as to adjust the voltage phases at the adjacent portions of the high voltage side electrodes to be equal (claims). Item 4).

[0012]

According to the gas laser device of the present invention, when a high frequency voltage is applied from an AC power supply between a plurality of pairs of high-voltage side electrodes and low-voltage side electrodes, an AC discharge is generated between the electrodes, so that the discharge is performed. The laser gas in the space is excited to generate laser light. In this case, since the power supply path by the AC power supply is provided with the phase synchronization means for matching the phases of the power supplies to the pairs of the high voltage side electrode and the low voltage side electrode, it is applied to a plurality of electrode pairs. The phase of the applied voltage is less likely to shift in the adjacent portions of the electrode pairs. Therefore, it becomes difficult to generate a standing wave due to electrical interference in the adjacent portion of the electrode pair, and it is possible to prevent a situation in which the laser output is reduced due to the non-uniform potential distribution on the electrode. become.

In the gas laser device according to the second aspect of the invention, since the feeding points for the plurality of high voltage side electrodes are arranged in line symmetry between the adjacent high voltage side electrodes, at each high voltage side electrode, another high voltage side from the feeding point. The distribution constant up to the portion adjacent to the side electrode becomes constant. Therefore, when a voltage is applied to each pair of the high-voltage side electrode and the low-voltage side electrode, the phase shift in the adjacent portion of the electrode pair becomes small, so that it is possible to reliably prevent the situation where the laser output is reduced. Become.

In the gas laser device according to the third aspect of the present invention, the feed points arranged in the above-mentioned line-symmetrical arrangement are arranged in the vicinity of the adjacent portions of each high voltage side electrode so as to face each other. It is possible to further reduce the phase shift in the adjacent portion of the electrode pair.

In the gas laser device according to the fourth aspect of the present invention, a distributed constant circuit is provided between the pair of high-voltage side electrodes and low-voltage side electrodes so as to adjust the voltage phases of adjacent parts of the high-voltage side electrodes to be equal. Therefore, it is possible to further reduce the phase shift in the adjacent portion in the state where voltage is applied to each pair of the high-voltage side electrode and the low-voltage side electrode, and to contribute to the prevention of the reduction of the laser output. become.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a schematic structure of the gas laser device in a state where the vacuum container is removed. However, this gas laser device is of a type that suppresses the temperature rise of the laser gas by utilizing heat conduction, and does not include a blower or the like for gas circulation.

In FIG. 1, for example, two high voltage side electrodes 11 and 12 provided are arranged on the same plane in the arrow A direction (laser optical axis direction). These high voltage side electrodes 11 and 12 are formed in a rectangular flat plate shape having a cavity through which cooling water flows, and their upper surfaces have cooling water inlets 11a and 12a and cooling water outlets 11b and 12b. Is provided. Further, terminals 11c and 12c corresponding to the feeding points in the present invention are provided on the upper surfaces of the high voltage side electrodes 11 and 12, respectively. In this case, the terminals 11c and 12c are provided.
Are arranged in line symmetry with respect to the adjacent portions of the high voltage side electrodes 11 and 12, and are arranged in the vicinity of the adjacent portions so as to face each other.

The low-voltage side electrode 13 is formed in the shape of a rectangular flat plate which is paired with each of the high-voltage side electrodes 11 and 12, and in parallel with the high-voltage side electrodes 11 and 12, the electrodes 11 and 12 are formed. The discharge space 14 is disposed between the two. The low-voltage side electrode 13 also has a cavity through which cooling water flows, and a lower surface provided with a cooling water inlet and a cooling water outlet (both not shown). In the discharge space 14, for example, CO
A laser gas composed of a mixed gas of 2, N2 and He is sealed at a predetermined pressure.

At both ends of the discharge space 14 in the direction of arrow A, a rear mirror 15 and an output mirror 16 which constitute a resonator are provided.
Is arranged. Further, the high-voltage side electrodes 11 and 12 and the low-voltage side electrode 13 are connected at a plurality of positions on the side parallel to the arrow A direction by a plurality of shunt inductance coils 17 forming a distributed constant circuit. By the shunt inductance coil 17, the high voltage side electrodes 11 and 1
The voltage phases are adjusted so that the voltage phases of the two adjacent portions are equal to each other. The shunt inductance coil 17 is made by processing a conductive material into a suitable shape such as a wire, plate, foil or mesh.

The high-frequency alternating-current power amplifiers 18 and 19 constituting the alternating-current power supply are provided corresponding to the high-voltage side electrodes 11 and 12, respectively, and generate a predetermined high-frequency voltage (frequency of about 10 MHz to 10 GHz). The voltage is applied to the terminals 11c and 12c through a phase synchronization circuit 20 corresponding to the phase synchronization means in the invention.
The low voltage side electrode 13 is connected to a ground line via a terminal (not shown).

FIG. 2 shows the electrical structure of the phase lock circuit 20 and the parts related thereto, which will be described below. That is, the high frequency AC power amplifier 1
8 and 19 are configured to amplify the output of the high frequency oscillator 21, and the output of one power supply amplifier 18 is the directional coupler 22 and the phase adjusting circuit 23 in the phase synchronization circuit 20.
To the terminal 11c of the high voltage side electrode 11 and the output of the other power amplifier 19 is the directional coupler 24.
It is provided to the terminal 12c of the high voltage side electrode 12 via the. The directional couplers 22 and 24
Uses an auxiliary arm to extract a signal proportional to only the voltage signal component traveling in the power supply direction (arrow B direction). Each of the signals thus extracted is a phase detection circuit 25 which is the core of the phase synchronization circuit 20. To be given to.

The phase adjustment circuit 23 includes a power amplifier 18
Is configured so that the phase of the power supply voltage applied via the directional coupler 22 can be selectively changed between the advance direction and the delay direction. Further, the phase detection circuit 25 has a phase difference between the proportional signals taken out from the auxiliary arms of the directional couplers 22 and 24, that is, a voltage signal having the same phase as the high frequency voltage applied to the high voltage side electrodes 11 and 12. Of the phase adjustment circuit 23 so that the phase difference becomes zero.
Is configured to operate. As a result of providing the phase locked loop circuit 20 configured in this way, the high voltage side electrode 11
The phase of the high frequency voltage applied between the low voltage electrode 13 and the low voltage electrode 13 is controlled to be equal to the phase of the high frequency voltage applied between the high voltage side electrode 12 and the low voltage electrode 13.

However, according to the above configuration, when a high frequency voltage is applied between the high voltage side electrodes 11 and 12 and the low voltage side electrode 13 from the high frequency AC power amplifiers 18 and 19, the electrodes 11 and 12 and the electrode In response to the generation of an AC discharge with the laser beam 13, the laser gas in the discharge space 14 is excited to generate laser light. The laser light thus generated is emitted from the rear mirror 15 and the output mirror 16. After being amplified in the process of reflecting the light, the light is output from the output mirror 16.

In this case, in each power supply path from the high frequency AC power amplifiers 18 and 19 to the high voltage side electrodes 11 and 12, a phase synchronization circuit 20 which works so as to match the phases of the applied voltages to the high voltage side electrodes 11 and 12 is provided. Is provided, the phase of the high frequency voltage applied to each of the high voltage side electrodes 11 and 12 is unlikely to shift in the adjacent portions of the electrodes 11 and 12. Therefore, a standing wave due to electrical interference is less likely to be generated in the adjacent portions of the high voltage side electrodes 11 and 12, and the laser output is reduced due to the non-uniform potential distribution on the electrodes 11 and 12. The situation can be prevented in advance.

Further, the terminals 11c and 12c, which are power feeding points for the high voltage side electrodes 11 and 12, are arranged in line symmetry between the adjacent high voltage side electrodes 11 and 12, and are arranged in a state of facing each other in the vicinity of the adjacent portion. Therefore, in each of the high voltage side electrodes 11 and 12, the distribution constant from each terminal 11c and 12c to the adjacent portion becomes small and the value becomes constant.
Therefore, when a high-frequency voltage is applied to the high-voltage electrodes 11 and 12, the phase shift in the adjacent portions of the electrodes 11 and 12 becomes small, so that the above-described laser output reduction prevention function is surely exhibited. become able to.

Further, a shunt inductance coil 17 is provided between each of the high-voltage side electrodes 11 and 12 and the low-voltage side electrode 13 so as to adjust the voltage phases of adjacent portions of the high-voltage side electrodes 11 and 12 to be equal to each other. Since it is provided, it is possible to further reduce the phase shift in the adjacent portion in the state where the voltage is applied between the high voltage side electrodes 11 and 12 and the low voltage side electrode 13, and also from this aspect. It becomes possible to contribute to the prevention of the reduction of the laser output.

The present invention is not limited to the above embodiment, but can be modified or expanded as follows. Although the phase synchronization circuit 20 is provided as the phase synchronization means, the pair of power supply lines to the high voltage side electrodes 11 and 12 themselves may be used as the phase synchronization means. That is, for example, by selecting the length of each of the power supply lines, the phase of the high frequency voltage applied between the high voltage side electrode 11 and the low voltage electrode 13 and the high frequency voltage applied between the high voltage side electrode 121 and the low voltage electrode 13 are selected. The phases of the generated high frequency voltage may be equal to each other.

Terminals 11c and 12c, which are feeding points for the high voltage side electrodes 11 and 12, are arranged in line symmetry between the adjacent high voltage side electrodes 11 and 12, and are arranged to face each other in the vicinity of the adjacent portions. However, it is also possible to adopt a configuration having only a line symmetrical arrangement. Although individual high-frequency AC power supply amplifiers 18 and 19 are provided as the AC power supply, the power may be supplied through a line shunted from the same AC power supply. Also, three or more high voltage side electrodes can be provided.

The device according to the above embodiment can also be used as an amplifying device for amplifying laser light introduced from the outside. Although configured as a carbon dioxide gas laser device, it can also be applied to a carbon monoxide gas laser device, an excimer laser device, and the like. Although the high-voltage side electrodes 11 and 12 and the low-voltage side electrode 13 are formed in a rectangular flat plate shape, they may be formed in other shapes such as a cylindrical shape, or each electrode can be formed by vapor-depositing a dielectric on metal. Although water is used as the cooling medium for the high voltage side electrodes 11 and 12 and the low voltage side electrode 13, another cooling medium such as liquid nitrogen may be used, or an air cooling system may be used.

[0030]

As is apparent from the above description, according to the first aspect of the invention, the high frequency voltage from the AC power supply is applied between the high voltage side electrode and the low voltage side electrode provided in plural pairs. In the gas laser device, the power supply path by the AC power supply is provided with the phase synchronization means for matching the phases of the power supplies to the pairs of the high-voltage side electrode and the low-voltage side electrode. Even when a plurality of electrodes are provided, there is a beneficial effect that electrical interference between the electrode pairs can be suppressed and a situation in which the laser output is reduced can be prevented.

According to a second aspect of the present invention, the feeding points for the plurality of high voltage side electrodes are arranged so as to be line-symmetrical between the adjacent high voltage side electrodes. According to the invention, since the feeding points having the above-mentioned line-symmetrical arrangement are arranged in the state of being opposed to each other in the vicinity of the adjacent portions of each high-voltage side electrode, the phase shift in the adjacent portion of the electrode pair is prevented. The size can be reduced, and the above-described laser output reduction prevention function can be reliably exerted.

According to a fourth aspect of the present invention, a distributed constant circuit is provided between the pair of high-voltage side electrodes and low-voltage side electrodes so as to adjust the voltage phases in adjacent portions of each high-voltage side electrode to be equal. Therefore, it is possible to further reduce the phase shift in the adjacent portion in the state where the voltage is applied to each pair of the high-voltage side electrode and the low-voltage side electrode, which can also contribute to the prevention of the reduction of the laser output from this aspect. Like

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is an electrical configuration diagram.

FIG. 3 is a vertical sectional view showing a conventional example.

[Explanation of symbols]

In the drawing, 11 and 12 are high-voltage side electrodes, 11c and 12c are terminals (feed points), 13 is low-voltage side electrodes, 14 is a discharge space, 17 is a shunt inductance coil (distributed constant circuit), and 18 and 19 are high-frequency AC. Power amplifier (AC power supply), 20 is a phase synchronization circuit (phase synchronization means), 22, 2
Reference numeral 4 is a directional coupler, 23 is a phase adjusting circuit, and 25 is a phase detecting circuit.

Claims (4)

[Claims] 1. A plurality of pairs of a high-voltage side electrode and a low-voltage side electrode arranged in a state of being opposed to each other with a discharge space filled with a laser gas interposed therebetween, and a high-frequency voltage from an AC power supply between the high-voltage side electrode and the low-voltage side electrode. In the gas laser device adapted to apply a voltage, a phase synchronization means for matching the phases of the power supplies to each pair of the high-voltage side electrode and the low-voltage side electrode is provided in the power supply path by the AC power source. And gas laser equipment. 2. The gas laser device according to claim 1, wherein the feeding points for the plurality of high-voltage electrodes are arranged in line symmetry between adjacent high-voltage electrodes. 3. The gas laser device according to claim 2, wherein the feeding points for the plurality of high voltage side electrodes are arranged in the vicinity of adjacent portions of each high voltage side electrode so as to face each other. 4. A distributed constant circuit is provided between a pair of the high-voltage side electrode and the low-voltage side electrode so as to adjust the voltage phases of adjacent portions of the high-voltage side electrodes to be equal to each other. The gas laser device according to any one of claims 1, 2 and 3.