JP2014110321A - Gas laser oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas laser oscillator capable of increasing laser output by solving a problem in conventional gas laser oscillators in which since the flow rate of a laser gas to a laser tube is determined by a rectifier, the maximum value of laser output is limited by the flow rate; and since only one inflow port is located at the upstream side, the temperature at the downstream side rises largely, and when the injection power is increased, population inversion is hardly formed and the laser output is hardly increased.SOLUTION: The gas laser oscillator generates a laser beam by performing discharge excitation on a laser medium flowing through a discharge tube. The gas laser oscillator comprises: a power source for performing the discharge excitation on the laser medium flowing through the discharge tube; an electrode connected to the power source; and a gas flow change mechanism that changes the laser medium into a gas flow optimized for the discharging and guides the gas flow into the discharge tube. In addition to the gas flow change mechanism, a gas guide port is formed at the downstream side of the gas flow change mechanism.

Description

  The present invention relates to a technique for increasing laser output in a gas laser oscillation device that generates laser light by discharging excitation of a laser medium flowing in a discharge tube.

  In general, a sheet metal processing apparatus using a gas laser oscillator is desired to be able to cut and weld different things such as a thin plate to a thick plate, or a kind of plate material, mild steel, aluminum, stainless steel, etc. without setting up.

  FIG. 3 shows an example of an axial flow type gas laser device as an example of a schematic configuration of a conventional gas laser oscillation device. Hereinafter, a conventional gas laser oscillation apparatus will be described with reference to FIG.

  In this figure, 131 and 141 are discharge tubes made of a dielectric material such as glass, 132, 133, 142 and 143 are electrodes provided around the discharge tubes 131 and 141, and hatched portions 135 and 145 are A discharge space is sandwiched between the electrodes 132, 133, 142, and 143, respectively.

  In this figure, the discharge spaces 135 and 145 are represented by oblique lines to distinguish them from the discharge tubes 131 and 141. As described above, normally, there are a plurality of discharge tubes sandwiched between electrodes, and the discharge tubes 131 and 141 are arranged along the optical axis 109 of the laser beam represented by a one-dot chain line.

  Reference numeral 105 denotes a final-stage mirror that substantially totally reflects, and reference numeral 106 denotes a partially-reflecting output mirror. It is arrange | positioned at both ends and forms the optical resonator. Further, a high voltage of several tens of kV is applied to the normal electrode portion, and the final-stage mirror and the output mirror are insulated by providing non-discharge tubes 151 and 152 made of a dielectric material such as glass between the electrodes.

  The arrows 121 and 122 indicate the direction in which the laser medium gas flows. 111 and 121 are gas flow changing mechanisms, 115 is an exhaust pipe block for collecting laser medium gas flowing out from the discharge tubes 131 and 141, and 123 is a laser medium gas discharged from the exhaust pipe block 115.

  Reference numerals 161 and 162 denote high-voltage power supplies for applying a voltage to the discharge electrodes. Although not shown in the figure, the laser medium gas is cooled between the gas flow changing mechanisms 111 and 112 and the exhaust pipe block 113 at a pressure of about 10 to 30 kPa. A heat exchanger for circulation and a circulation pump are provided.

  The above is the configuration of the conventional gas laser oscillation apparatus. Next, the operation thereof will be described.

  The laser medium gas 121 that has passed through the gas flow changing mechanism 111 and has been changed to a gas flow optimized for discharge is introduced into the discharge tube 131. In this state, discharge energy is obtained from the electrodes 132 and 133 and excited, and a discharge is generated in the discharge space 135. The laser medium gas in the discharge space 135 flows into the exhaust pipe block 115 and becomes the laser medium gas 123 and returns to the circulation pump. At this time, there is no gas flow in the non-discharge tube 151, no discharge is generated, and insulation between the discharge space 135 and the output mirror 106 is maintained.

  Similarly, the laser medium gas 122 passes through the gas flow changing mechanism 112, is changed to a gas flow optimized for discharge, is introduced into the discharge tube 141, and forms a discharge space 145 like the discharge tube 131.

  These excited laser medium gases are resonated by an optical resonator formed by the output mirror 106 and the final stage mirror 105, and laser light 109 is output from the output mirror 106. Reference numerals 134 and 144 denote auxiliary electrodes for facilitating discharge ignition.

JP-A-2-2677982

  When the conventional technique as described above is used, the gas flow changing mechanisms 111 and 112 are the only positions where the laser medium gas is introduced into the discharge tubes 131 and 141. In order to change the gas flow, it is common to install a component that changes the gas flow in the normal pipe, and the component acts as a resistance to the gas flow and reduces the flow rate. Therefore, the maximum value of the laser output is restricted by the gas flow changing mechanism.

  In addition, when increasing the maximum laser output by increasing the voltage applied to the electrode section, the gas temperature rises, and in particular, the temperature on the downstream side of the discharge tube cannot form an inverted distribution, and the maximum laser output is increased. The value is limited.

  An object of the present invention is to provide a small-sized and high-power laser oscillation device capable of increasing the maximum value of laser output in view of the above-described conventional problems.

  In order to achieve the above object, in the gas laser oscillation apparatus of the present invention, an inflow port through which laser gas flows is provided in a discharge tube downstream of the gas flow rectification mechanism. With these configurations, the laser gas can be introduced from the downstream side, and since the flowing laser medium gas is sufficiently cooled, the effect of reducing the temperature of the downstream laser gas can be obtained. As described above, the oscillation efficiency can be increased, and a high-power laser beam can be obtained even when the same electric power as in the conventional case is injected. In many cases, the discharge tube is provided with an auxiliary electrode for lowering the start voltage of discharge and reducing variations. By providing the downstream gas introduction port in the vicinity of the auxiliary electrode, the ionized laser medium gas formed in the vicinity of the auxiliary electrode at the start of discharge can easily flow, and the ignition is stabilized. As a result, a higher voltage can be applied to the discharge tube, so that the power injected into the discharge tube can be increased. As described above, a high-power laser beam can be obtained even with a discharge tube of the same size.

  With the configuration of the present invention described above, a high-power laser beam can be obtained even with a discharge tube of the same size. Thereby, high speed or thicker plate laser processing can be provided. If the output is the same, the oscillator can be miniaturized.

Schematic configuration diagram of a laser oscillation device in an embodiment of the present invention The graph which shows the state of the laser gas temperature of the laser oscillation apparatus in embodiment of this invention Schematic configuration diagram of a laser oscillation device in the prior art

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the invention.

  FIG. 1 is a schematic configuration diagram of a gas laser oscillation apparatus according to the present invention, which will be described below with reference to FIG.

  In this figure, 31 and 41 are discharge tubes made of a dielectric material such as glass, 32, 33, 42 and 43 are electrodes provided around the discharge tubes 31 and 41, and hatched portions 35 and 45 are A discharge space is sandwiched between the electrodes 32, 33, 42, and 43, respectively. In this figure, the discharge spaces 35 and 45 are represented by oblique lines to distinguish them from the discharge tubes 31 and 41. As described above, usually, there are a plurality of discharge tubes sandwiched between electrodes, and the discharge tubes 31 and 41 are arranged along the optical axis 9 of the laser beam represented by a one-dot chain line.

  Reference numeral 5 denotes a final stage mirror that substantially totally reflects, and reference numeral 6 denotes an output mirror that partially reflects. The final stage mirror 5 and the output mirror 6 are arranged on the entire discharge space disposed on the optical axis 9 (represented by a one-dot chain line). It is arrange | positioned at both ends and forms the optical resonator.

  In addition, a high voltage of several tens of kV is applied to the normal electrode portion, and the final-stage mirror 5 and the output mirror 6 are insulated by providing non-discharge tubes 51 and 52 made of a dielectric material such as glass between the electrodes. .

  The arrows 21, 22, 23, and 25 to 28 indicate the direction in which the laser gas flows. 11 and 12 are gas flow changing mechanisms, and 15 is an exhaust pipe block for collecting laser medium gas flowing out from the discharge tubes 31 and 41.

  Reference numerals 61 and 62 denote high-voltage power supplies for applying a voltage to the discharge electrodes. Although not shown in the figure, the supply pipe block, the gas flow changing mechanisms 11 and 12, and the exhaust pipe block 15 are laser-treated at a pressure of about 10 to 30 kPa. A heat exchanger and a circulation pump for cooling and circulating the medium gas are provided.

  Next, the operation will be described.

  The laser medium gas 25 that has passed through the gas flow changing mechanism 11 is adjusted to a gas flow suitable for discharge by the gas flow changing mechanism 11 and introduced into the discharge tube 31. The laser medium gas that normally flows into the discharge tube 31 is cooled by a heat exchanger in order to increase the oscillation efficiency of the laser. Usually, the temperature of the gas is cooled to 20 to 30 ° C. In this state, discharge energy is obtained from the electrodes 32 and 33 and excited to generate discharge in the discharge space 35.

  The laser medium gas in the discharge space 35 flows into the exhaust pipe block 15 and becomes the laser medium gas 23 and returns to the circulation pump. The laser medium gas 23 is partly converted into laser light described below by the energy of discharge, and the remaining discharge energy increases the temperature of the gas. At this time, there is no gas flow in the dischargeless tube 51, and no discharge is generated, and the insulation between the discharge space 35 and the last stage mirror 5 is maintained.

  Similarly, the laser medium gas 26 is introduced into the discharge tube 41 to form a discharge space 45 in the same manner as the discharge tube 31.

  These excited laser medium gases are resonated by an optical resonator formed by the output mirror 6 and the final stage mirror 5, and laser light 9 is output from the output mirror 6.

  When the discharge energy is increased in order to obtain a high-power laser output, the temperature of the laser gas in the discharge tube rises. In the carbon dioxide laser oscillator, when the temperature exceeds about 200 ° C., it becomes difficult to form an inversion distribution, the oscillation efficiency is lowered, and the laser output does not increase even if the discharge energy is increased.

  In the present invention, the discharge tube 31 is provided with the gas introduction port 13 for introducing the laser medium gas downstream from the gas flow changing mechanism 11 so that the laser medium gas flows in the discharge tube. Similarly, the discharge tube 41 is also provided with a gas inlet 14 so that a laser medium gas flows in the discharge tube.

  By adopting the above-described configuration, the pressure loss in the gas path of the laser medium is reduced, and more laser medium gas can be flowed into the discharge tube. Further, the temperature of the laser medium gas on the downstream side is reduced by introducing the laser medium gas cooled by the heat exchanger from the gas inlet on the downstream side of the gas flow changing mechanism.

  FIG. 2 is an explanatory diagram of the laser gas temperature of the laser oscillator according to the embodiment of the present invention. As can be seen, the inversion distribution of the laser medium gas can be easily formed across the entire discharge tube.

  In many cases, the discharge tube is provided with an auxiliary electrode for lowering the start voltage of discharge and reducing variations. By providing the gas inlets 13 and 14 on the downstream side in the vicinity of the auxiliary electrodes 34 and 44, the laser medium gas in the ionized state formed in the vicinity of the auxiliary electrode at the start of discharge can easily flow, and the ignition is stabilized. With the above configuration, the configuration of the present invention can be established.

  The gas laser oscillation apparatus according to the present invention can provide high-power laser light even with a discharge tube of the same size, so that it can provide laser processing of a high-speed or thicker plate with the same output. For example, the oscillator can be miniaturized, and is useful in a gas laser oscillation apparatus that generates laser light by exciting the laser medium flowing through the discharge tube.

5 Final mirror (total reflection mirror)
6 Output mirror (partial reflection mirror)
9 Laser light 11, 12 Gas flow changing mechanism 13, 14 Gas inlet 15 Exhaust piping block 21, 22 Laser medium gas flow direction 23 Laser medium gas discharge direction 25, 26 Laser medium gas flow 27, 28 flowing through gas flow changing mechanism Laser medium gas flow 31, 41 Discharge tube 32, 33, 42, 43 Electrode 34, 44 Auxiliary electrode 35, 45 Discharge space 51, 52 Non-discharge tube 61, 62 Power supply 105 Final stage mirror (total reflection) mirror)
106 Output mirror (partial reflection mirror)
109 Laser beam optical axis 111, 112 Gas flow changing mechanism 115 Exhaust piping block 121, 122 Laser medium gas flow direction 123 Laser medium gas discharge direction 131, 141 Discharge tube 132, 133, 142, 143 Electrode 135, 145 Discharge space 151 , 152 Non-discharge tube 161, 162 Power supply

Claims (3)

A gas laser oscillation device having one or a plurality of discharge tubes and generating laser light by discharging and exciting a laser medium flowing through the discharge tube, for discharging and exciting the laser medium in the discharge tube A power source, an electrode connected to the power source, and a gas flow changing mechanism for changing the laser medium into a gas flow optimized for discharge and introducing the gas into the discharge tube, and a gas downstream of the gas flow changing mechanism. A gas laser oscillation device provided with a gas inlet separately from the flow changing mechanism. A gas laser oscillation device characterized in that the gas introduction port is provided on the downstream side of half of the entire length of the discharge tube. The gas laser oscillation apparatus according to claim 1 or 2, wherein the gas introduction port is provided in the vicinity of an auxiliary electrode for assisting discharge ignition.

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