JP3427338B2 - Microwave-excited gas laser oscillator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique of a microwave excitation gas laser oscillator which is an energy source of a laser processing machine.

[0002]

2. Description of the Related Art In recent years, laser processing machines have been used for processing metal products and non-metal products, contributing to automatic unmanned work sites and improved production efficiency. Further, in the market, there is a demand for a high-power laser processing machine that is compact and can output stable output in order to use a plurality of laser processing machines more efficiently. In response to these market demands, microwave-excited gas laser oscillators capable of achieving high injection energy have been developed.

A conventional microwave-excited gas laser oscillator will be described below. FIG. 7 is a schematic diagram of a discharge part of a conventional microwave excitation gas laser oscillator.
In FIG. 7, 51 is a discharge tube that limits the discharge area, and 52 is a discharge tube.
Is a power supply that supplies the energy required for excitation together with the magnetron 53, 54 is a rectangular waveguide that transmits microwaves, and 55 is a discharge tube holder that fixes the discharge tube 51 to the main flange 56 and the exhaust block 57.

In FIG. 7, two waveguides 54 are assembled in series in one discharge tube 51 to provide two discharge areas. That is, each discharge area has one waveguide and discharge tube 51.
Determined by

The operation of the microwave-excited gas laser oscillator configured as described above will be described below. First, the laser gas as the excitation medium flows into the discharge tube 51 from the main flange 56. On the other hand, the power source 52 drives the magnetron 53, and the microwave generated by the magnetron 53 is transmitted to the discharge tube 51 through the waveguide 54 to excite the laser gas and form a discharge area.

[0006]

However, in the above-mentioned conventional configuration, in the microwave-excited gas laser oscillator, in order to obtain a high output, one discharge tube is provided with two or more waveguides, that is, It is necessary to provide two or more discharge areas in one discharge tube (JP-A-61-220486).
Japanese Patent Laid-Open Publication No. 3-125485). In this case, at the time of high output, there is no brightness in the central portion of the discharge tube, and the discharge brightness exists only near the inner wall of the discharge tube, and the output cannot be taken out.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a microwave excitation gas laser oscillator capable of extracting a high output.

[0008]

SUMMARY OF THE INVENTION The present invention for solving the above problem is provided with a discharge zone 2 or more, following the discharge zone
The discharge area of the step is connected with a metal body having a hollow portion through which laser gas passes . By this means, the temperature of the laser gas in the discharge area can be lowered and a high output can be taken out.

In another invention of the present invention, both ends of a discharge tube constituting a laser gas flow path are made of a metal body having a hollow portion . By this means, the discharge tube can be cooled, the annular discharge can be suppressed, and high output can be taken out.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is a laser gas as an excitation medium, a discharge tube for limiting a discharge area, a power supply and a magnetron for supplying energy necessary for excitation, and the energy. A waveguide for transmitting
Equipped with two or more discharge areas, the discharge area next to the discharge area
The region is connected by a metal body having a hollow portion that allows the laser gas to pass therethrough , and when the high temperature laser gas passes through the hollow portion of the metal body, the metal body cools the temperature of the laser gas. And the laser gas flowing into the discharge area of the next stage is excited again like the discharge area of the previous stage.

The invention according to claim 2 of the present invention is
The inner diameter of the metal body is made the same as the inner diameter of the discharge tube, and when the laser gas passes through the hollow portion of the metal body, it contacts the inner wall of the hollow portion of the metal body having a low temperature and is cooled.

The invention according to claim 3 of the present invention is
The inner diameter of the metal body is larger than the inner diameter of the discharge tube.
The laser gas becomes a turbulent flow, and has the effect of lowering its temperature due to heat exchange with the inner wall of the hollow portion of the metal body and turbulent flow of the laser gas.

The invention according to claim 4 of the present invention is
The inner diameter of the metal body is smaller than the inner diameter of the discharge tube.
The inner diameter of the metal body serves as an aperture that limits the mode of light output formed by exciting the laser gas, and any mode of light output can be taken out.

The invention according to claim 5 of the present invention is
The inner diameter of the metal body connecting the two or more discharge areas is made smaller along the laser gas flow, and the hollow portion of the metal body which is successively reduced in diameter has the same optical output as in claim 4. The mode of can be taken out.

The invention according to claim 6 of the present invention is
The inner diameter of the metal body connecting the two or more discharge areas is made larger along the laser gas flow, and the laser gas flowing into the hollow portion of the metal body contacts the inner wall of the metal body and is cooled. In addition, turbulence is promoted, the temperature of the laser gas is lowered, and the laser gas flow in the discharge area can be changed.

The invention according to claim 7 of the present invention is
The metal body connecting two or more discharge areas is a gas chamber, which cools the gas laser and supplies different laser gas flows into the discharge areas in the same manner as the operation of the invention of claim 1. It has the effect of affecting the output.

The invention according to claim 8 of the present invention is
The inner diameter of the metal body that connects two or more discharge areas is changed according to the laser beam profile, and precise mode control can be performed.

The invention according to claim 9 of the present invention is
In the invention according to claim 1 , both ends of the discharge tube forming the discharge area are made of metal bodies having hollow portions, and the laser gas is cooled by the metal bodies at both ends to suppress annular discharge.

According to a tenth aspect of the present invention, in the invention according to the first aspect, the inner surface of the discharge tube is used as a catalyst for promoting the reaction of the laser gas, and one of the gases dissociated by excitation is used. The part contacts the catalyst on the inner surface of the discharge tube , is reduced to laser gas, and is used for processing.

In the eleventh aspect of the present invention, the energy supply means is a waveguide having a structure in which the laser gas is excited by a plurality of microwaves in which the electric fields of the discharge part vibrate in different directions. It is possible to obtain a microwave-excited gas laser oscillator that excites well and has a high output.

(Embodiment 1) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. 1 shows a schematic configuration of a discharge unit according to Embodiment 1 of the present invention.
3 shows a cross section near the discharge part in the first embodiment of the present invention. 1 and 2, 1 is a discharge tube that limits the discharge area in the circumferential direction, 2 is a power supply that supplies energy necessary for excitation together with the magnetron 3, 4 is a rectangular waveguide that transmits microwaves, and 5 is A discharge tube holder for fixing the discharge tube 1 to the waveguide 4. The discharge tube 1, magnetron 3, waveguide 4 and discharge tube holder 5 constitute one discharge unit. FIG. 1 and FIG. 2 show a state in which two discharge units constitute a discharge part.
Reference numeral 6 is an inflow cylinder for fixing the discharge unit to the main flange 7, 8 is a first connection cylinder as a metal body having a hollow portion for connecting the discharge unit, and 9 is an outflow cylinder for fixing the discharge unit to the exhaust block 10. . A catalyst that reacts with the laser gas and reduces the dissociated gas to the laser gas is present on the inner wall of the outflow cylinder 9. The inflow cylinder 6, the first connection cylinder 8 and the outflow cylinder 9 are all made of metal and are water-cooled. FIG. 2 shows a cross section of the first connecting cylinder 8. The inner diameter of the first connecting tube 8 is the same as the inner diameter of the discharge tube 1. Further, in FIG. 1, one end of the discharge unit installed upstream of the laser gas is fixed to the main flange 7 via the inflow tube 6, and the other end is the first
It is connected to the discharge unit in the next stage, that is, on the downstream side with respect to the laser gas, via the connecting cylinder 8. On the other hand, one end of the discharge unit installed on the downstream side of the laser gas is connected to the discharge unit on the preceding stage, that is, installed on the upstream side of the laser gas via the above-mentioned first connecting tube 8, and the other end flows out. It is fixed to the exhaust block 10 via the cylinder 9.

The operation of the microexcitation gas laser oscillator configured as described above will be described. The laser gas that is the excitation medium flows from the main flange 7 through the inflow tube 6 into the discharge tube 1 that is the discharge area. At this time, the excitation energy generated and transmitted by the power supply 2, the magnetron 3, and the waveguide 4 is supplied to the laser gas to excite the laser gas. The laser gas excited in the discharge area flows out of the discharge area, flows into the first connecting cylinder 8, and changes from the excited state to the ground state. At this time, the laser gas has just been excited and the laser gas temperature is very high. Water-cooled first connecting cylinder 8
Lowers the laser gas temperature as it passes through,
It flows into the discharge area of the next stage. The laser gas is excited again like the discharge area in the previous stage, and flows out to the exhaust block 10 via the outflow tube 9. When passing through the outflow tube 9, a part of the gas dissociated by excitation is reduced to a laser gas by the catalyst on the inner wall of the outflow tube 9 and used.

As described above, according to the first embodiment, the high temperature laser gas immediately after the discharge is cooled by connecting the discharge areas with the first connecting cylinder 8 which is a cooled metal body. And the laser gas temperature is lowered. Due to this decrease in the laser gas temperature, the oscillation efficiency in the discharge area where excitation is continued is improved, and a stable and high output microwave excited gas laser oscillator can be provided.

In the first embodiment, two waveguides 4 are provided to form two discharge areas. However, if three or more discharge areas are provided and each discharge area is connected in series with an extension tube, the same result is obtained. In addition, in the first embodiment, the first connecting tube 8 can be obtained.
The same effect can be obtained by cooling with water but with oil, or by cooling with air by providing a radiation fin. Further, although the waveguide 4 is rectangular in the first embodiment, the same effect can be obtained by using a waveguide having a structure in which the laser gas is excited by a plurality of microwaves in which the electric fields of the discharge part vibrate in different directions. .

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIG. FIG. 3 shows a cross section in the vicinity of the discharge part according to the second embodiment of the present invention.
In the configuration, the first connection cylinder 8 in FIG. 2 is replaced with the second connection cylinder 11, and the other configurations are the same.

In FIG. 3, the discharge areas are connected by a second connecting tube 11 having an inner diameter larger than the inner diameter of the discharge tube 1.

The operation of the microwave excitation gas laser oscillator configured as above will be described. Similar to the first embodiment, the laser gas excited in the discharge area installed on the upstream side of the laser gas flows out of the discharge area and flows into the second connecting cylinder 11 to change from the excited state to the ground state. Become. At this time, the laser gas has just been excited and the laser gas temperature is very high. Water-cooled second connecting tube 1
Since 1 has an inner diameter larger than the inner diameter of the discharge tube 1,
The laser gas flowing into the second connecting cylinder 11 becomes a turbulent flow,
The temperature of the laser gas decreases due to heat exchange with the inner wall of the second connecting cylinder 11 and turbulence of the laser gas.

As described above, according to the second embodiment, the discharge regions are connected by the second connecting cylinder 11 having a hollow portion made of a cooled metal body, and the inner diameter of the second connecting cylinder 11 is set to the discharge area. By setting the inner diameter of the discharge tube 1 to be smaller than that of the discharge tube 1, the high-temperature laser gas immediately after the discharge comes into direct contact with the inner wall of the cooled second connecting cylinder 11, and the turbulent flow of the laser gas is promoted to increase the laser gas temperature descend. Due to this decrease in the laser gas temperature, the oscillation efficiency in the discharge area where excitation is continued is improved, and a high-power microwave excited gas race oscillator can be provided.

(Third Embodiment) A third embodiment of the present invention will be described below with reference to FIG. 4 shows a cross section in the vicinity of the discharge part according to the third embodiment of the present invention.
The first connection tube 8 in is a third connection tube 12 made of a metal body and having a hollow portion, and the other configurations are the same.

In FIG. 4, the discharge areas are connected by a third connecting tube 12 having an inner diameter smaller than the inner diameter of the discharge tube 1.

The operation of the microwave excitation gas laser oscillator configured as above will be described. Similar to the first embodiment, the laser gas excited in the discharge area installed on the upstream side with respect to the laser gas flows out of the discharge area, flows into the third connecting tube 12, and is discharged to the next-stage discharge area. leak. At this time, since the water-cooled third connecting tube 12 has an inner diameter smaller than the inner diameter of the discharge tube 1, it serves as an aperture that limits the mode of optical output formed by exciting the laser gas inside the laser oscillator. Due to this limitation, the heat generated in the third connecting cylinder 12 serving as the aperture is removed by water cooling.

As described above, according to the third embodiment, the discharge areas are connected by the third connecting tube 12 having a hollow portion with a cooled metal body, and the inner diameter of the third connecting tube 12 is set to the discharge area. It is possible to provide a microwave pumped gas laser oscillator capable of taking out an arbitrary mode of optical output by making the diameter smaller than the inner diameter of the discharge tube 1 which limits the.

In the third embodiment, the third connecting tube 1
Although it has been mentioned only that the inner diameter of 2 is smaller than the inner diameter of the discharge tube 1, more precise mode control can be performed by changing the inner diameter of the third connecting tube 12 along the mode profile of the laser oscillator. .

(Fourth Embodiment) A fourth embodiment of the present invention will be described below with reference to FIG. FIG. 5 shows a cross section in the vicinity of the discharge part according to the fourth embodiment of the present invention.
The first connecting cylinder 8 in is a fourth connecting cylinder 13 made of a metal body and having a hollow portion, and the other configurations are the same.

In FIG. 5, the discharge areas are connected by a fourth connecting tube 13 having a gas chamber inside. FIG. 5 shows a fourth connecting cylinder 13 having an inner diameter that expands like a trumpet with respect to the laser gas flow.

The operation of the microwave excitation gas laser oscillator configured as above will be described. Similar to the first embodiment, the laser gas excited in the discharge area installed on the upstream side of the laser gas flows out of the discharge area and flows into the fourth connecting cylinder 13 to change from the excited state to the ground state. Become. At this time, the laser gas has just been excited and the laser gas temperature is very high. Water-cooled fourth connecting cylinder 1
Since the inside of 3 forms a gas chamber, the laser gas flowing into the discharge area of the next stage becomes a turbulent flow.

As described above, according to the fourth embodiment, the discharge regions are connected by the fourth connecting cylinder 13 having a hollow portion with a cooled metal body, and the inside of the fourth connecting cylinder 13 is connected to the gas chamber. By doing so, the high temperature laser gas immediately after the discharge comes into direct contact with the inner wall of the cooled fourth connecting cylinder 13, and the turbulent flow of the laser gas is promoted to lower the laser gas temperature. This lowering of the laser gas temperature improves the oscillation efficiency in the discharge area where excitation is continued, and a microwave pumped gas laser oscillator with high output can be provided.

Although the inside of the gas chamber has a trumpet shape in the fourth embodiment, different laser gas flows are supplied into the discharge area by changing the inside, for example, by cutting a groove in a spiral shape or by tapering. Affect the output. Also, by changing the inner diameter or the inner surface shape of the exhaust pipe, the laser gas flow in the discharge area changes, and a high output can be provided. Further, the same effect as that of the gas chamber can be obtained by sequentially increasing or decreasing the inner diameter of the connecting pipe along the laser gas flow, or by installing the inner diameter of the connecting pipe in combination along the laser gas flow.

(Fifth Embodiment) The fifth embodiment of the present invention will be described below with reference to the drawings. FIG. 6 is a cross section in the vicinity of the discharge part according to the fifth embodiment of the present invention and shows a cross section of one discharge area. The same components as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 6, reference numeral 14 is an alumina ceramics tube which is a dielectric having good thermal conductivity and good transmittance for microwaves, and 15 is an extension tube of a water-cooled metal body having a hollow portion. is there. Both end surfaces of the alumina ceramics tube 14 are connected to the extension tube 15 by brazing, for example, and constitute one discharge tube. The alumina ceramic tube 14 and the extension tube 15 are fixed to the waveguide 4 by a holder 16.

The operation of the microwave excitation gas laser oscillator configured as above will be described. First, the laser gas flowing into the extension tube 15 is excited in the waveguide 4 in the discharge area limited by the alumina ceramic tube 14.
At this time, the inner wall of the alumina ceramics tube 14 is cooled by heat conduction from the water-cooled extension tube 15 which is brazed to both ends of the alumina ceramics tube 14. By this cooling, the temperature of the laser gas is lowered, that is, the discharge brightness is not annular and the discharge is uniform, so that a high output can be obtained.

As described above, according to the fifth embodiment, a high output microwave excited gas laser oscillator is provided by brazing the extension tubes 15 to both ends of the alumina ceramic tube 14 to form a water cooled discharge tube. be able to.

In the fifth embodiment, the alumina ceramics tube 14 is used, but a dielectric material that transmits microwaves efficiently, is excellent in heat resistance, and has good thermal conductivity, for example, bebereria ceramics tube is used. Even if the same effect is obtained,
In addition, in the fifth embodiment, the extension pipes at both ends are directly cooled, but the same effect can be obtained by mounting the gold extension pipe water cooling jacket.

[0044]

As is apparent from the above description, according to the present invention, two or more discharge areas are provided, and a metal body having a hollow portion is used to connect between the discharge areas to obtain a high output. It is possible to realize a microwave-excited gas laser oscillator capable of performing the above.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a discharge unit according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the vicinity of the discharge part.

FIG. 3 is a sectional view of the vicinity of a discharge part according to the second embodiment of the present invention.

FIG. 4 is a sectional view of the vicinity of a discharge part according to a third embodiment of the present invention.

FIG. 5 is a sectional view of the vicinity of a discharge part according to a fourth embodiment of the present invention.

FIG. 6 is a sectional view of the vicinity of a discharge part according to a fifth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a discharge part of a conventional microwave excitation gas laser oscillator.

[Explanation of symbols]

1 discharge tube 2 power supplies 3 magnetron 4 Waveguide 6 inflow cylinder 8 First connection tube (metal body with hollow part) 9 Outflow tube 11 Second connection cylinder (metal body with hollow part) 12 Third connection cylinder (metal body with hollow part) 13 Fourth connection cylinder (metal body with hollow part) 14 Alumina ceramic tube 15 Extension pipe

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Claims (11)

(57) [Claims] 1. A laser gas as an excitation medium, a discharge tube for limiting a discharge area, a power supply and a magnetron for supplying energy necessary for excitation, a waveguide for transmitting the energy, and two or more discharge areas. Prepared and discharged from the area
A microwave-excited gas laser oscillator in which a metal body having a hollow portion for passing the laser gas is connected to the discharge area of the step . 2. The microwave excited gas laser oscillator according to claim 1, wherein the inner diameter of the metal body is the same as the inner diameter of the discharge tube. 3. The microwave excited gas laser oscillator according to claim 1, wherein the inner diameter of the metal body is larger than the inner diameter of the discharge tube. 4. The microwave excited gas laser oscillator according to claim 1, wherein the inner diameter of the metal body is smaller than the inner diameter of the discharge tube. 5. The microwave excited gas laser oscillator according to claim 1, wherein an inner diameter of the metal body connecting the two or more discharge areas is made smaller along the laser gas flow. 6. The microwave excited gas laser oscillator according to claim 1, wherein the inner diameter of the metal body connecting the two or more discharge areas is increased along the laser gas flow. 7. The microwave excited gas laser oscillator according to claim 1, wherein the metal body connecting two or more discharge areas is a gas chamber. 8. The microwave excited gas laser oscillator according to claim 1, wherein the inner diameter of the metal body connecting the two or more discharge areas is changed along the laser beam profile. 9. The microwave excited gas laser oscillator according to claim 1 , wherein both ends of the discharge tube constituting the discharge area are made of a metal body having a hollow portion. 10. The microwave excited gas laser oscillator according to claim 1, wherein the inner surface of the discharge tube is a catalyst for promoting the reaction of the laser gas. 11. The microwave excitation according to claim 1, wherein the energy supply means is a waveguide having a structure in which the laser gas is excited by a plurality of microwaves in which the electric field oscillation directions of the discharge part are different from each other. Gas laser oscillator.