JP2013247260A - Gas laser oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve quality of laser beams by inhibiting scattered light from being mixed into the laser beams in a gas laser oscillator.SOLUTION: A gas laser oscillator includes: a discharge tube which excites a laser medium arranged therein by giving energy; at least a pair of mirrors which are arranged on an optical axis of laser beams discharged from the laser medium excited by the discharge tube; and an alignment adjustment mechanism. The gas laser oscillator is characterized in that a groove with a tilt angle in the optical axis direction is provided in an adjustment mechanism part. The tilt angle is made to have 15 to 45 degrees.

Description

  The present invention relates to a gas laser oscillator and gas laser processing machine of kW class mainly used for sheet metal cutting.

  FIG. 6 shows an example of a schematic configuration of a conventional axial flow type gas laser oscillation device. Hereinafter, a conventional axial gas laser oscillator will be described with reference to FIG.

  In this figure, 101 is a discharge tube made of a dielectric material such as glass, and 102 and 103 are electrodes provided around the discharge tube. Reference numeral 104 denotes a power source connected to the electrodes. Reference numeral 105 denotes a discharge space in the discharge tube 101 sandwiched between the electrodes 102 and 103.

  Reference numeral 106 denotes a total reflection mirror, and reference numeral 107 denotes a partial reflection mirror. The total reflection mirror 106 and the partial reflection mirror 107 are fixedly disposed at both ends of the discharge space 5 to form an optical resonator. Reference numeral 108 denotes a laser beam output from the partial reflecting mirror 7.

  An arrow 109 indicates a laser gas flow, which circulates in the axial flow type gas laser oscillation device. 110 is a laser gas flow path, 111 and 112 are heat exchangers for lowering the temperature of the laser gas whose temperature has increased due to discharge in the discharge space 105 and the operation of the blower, and 113 is a blower means for circulating the laser gas. A gas flow of about 100 m / sec is obtained in the discharge space 105 by the means 113. The laser gas channel 110 and the discharge tube 101 are connected by a laser gas introduction unit 114.

  Reference numeral 118 denotes a spacer main body. In the prior art, a groove is provided in the vicinity of the discharge tube to suppress scattered light.

  FIG. 5 shows an example of a schematic configuration of a conventional sheet metal cutting laser processing machine. Hereinafter, a conventional laser beam machine will be described with reference to FIG.

  In this figure, the laser beam 8 is reflected by the reflecting mirror 31 and guided to the vicinity of the workpiece 32. The laser beam 8 is condensed into a high-density energy beam by a condensing lens 35 provided inside the torch 36, irradiated onto the workpiece 32, and cutting processing is performed. The workpiece 32 is fixed on a machining table 37, and the drive device 33 and the numerical control device 34 move the torch 36 relative to the workpiece 32 to perform machining of a predetermined shape.

  The above is the configuration of the conventional gas laser oscillation device and gas laser processing machine. Next, the operation will be described.

  The laser gas sent out from the blowing means 113 passes through the laser gas flow path 110 and is introduced into the discharge tube 1 from the laser gas introduction part 114. In this state, a discharge is generated in the discharge space 105 from the electrodes 102 and 103 connected to the power source 104. The laser gas in the discharge space 105 is excited by obtaining this discharge energy. The excited laser gas is brought into a resonance state by an optical resonator formed by the total reflection mirror 106 and the partial reflection mirror 107, and the laser is emitted from the partial reflection mirror 7. A beam 108 is output. This laser beam 108 is used for applications such as laser processing.

JP 2002-252396 A

  Such a conventional gas laser oscillation device has the following problems.

  In the above conventional laser oscillation device, it is ideal that only the light parallel to the optical axis 115 is amplified and extracted as the laser beam 108 when the laser beam is resonated in the optical resonator. Causes scattered light 117 that is not parallel to the optical axis 115 due to reflection or diffraction. When the scattered light 117 is mixed into the laser beam 108, the quality of the laser beam 108 is degraded. For example, when performing laser cutting, there is a problem that the cutting speed is decreased.

  As a conventional approach for solving this problem, a scattered spacer is mixed in the laser beam 108 by arranging a hollow spacer 118 called an aperture and blocking the scattered light by providing a groove on the inner surface of the hollow spacer 118. Attempts have also been made to suppress this.

  However, the laser light is subjected to angle adjustment called alignment for increasing the oscillation efficiency. The alignment is adjusted by a holder 116 that holds the output mirror 107 and the final stage mirror 106 and has an adjustment mechanism for adjusting the angle. Therefore, the angles of the optical axis 115 made of mechanical parts, the output mirror 107, and the final stage mirror 106 are not necessarily perpendicular.

  As described above, it is ideal that only the light parallel to the optical axis 115 is amplified and extracted as the laser beam 8 during the laser light resonance in the optical resonator. As a result, scattered light 21 that is not parallel to the optical axis 115 is generated. In addition, since the diffraction and reflection angles vary depending on the alignment, it was not possible to obtain a sufficient effect of suppressing scattered light due to the degree of optical axis adjustment and component variations.

  The present invention has been made in view of the above problems.

  In order to solve the above-described problems, the present invention provides a discharge tube for exciting a laser medium disposed inside by applying energy, and an optical axis of laser light emitted from the laser medium excited by the discharge tube. It has at least a pair of arranged mirrors, and has an alignment adjustment mechanism for holding the mirror, and a groove having an inclination angle with respect to the optical axis direction is provided in the adjustment mechanism portion. The gas laser oscillator and the gas laser processing machine are characterized in that the adjusting mechanism member material is 15 to 45 degrees, the material of the adjusting mechanism is aluminum, and carbon is vapor-deposited on the spacer surface or the grooved material having the inclined angle is ceramic.

  According to the present invention, it is possible to suppress the scattered light from being mixed into the laser beam and improve the quality of the laser beam. Thereby, it is possible to improve processing performance such as improvement of the cutting speed in laser processing and reduction of the cutting width.

1 is a block diagram of a gas laser oscillation apparatus according to an embodiment of the present invention. FIG. 6 is a detailed diagram of a spacer of a gas laser oscillation apparatus according to claims 1 to 6 in an embodiment of the present invention. Relationship diagram between the inclination angle of the groove with respect to the optical axis direction and the amount of scattered light absorbed in the laser beam in the same embodiment Relationship diagram between the amount of laser light and the amount of scattered light in the laser beam in the same embodiment Configuration diagram of conventional gas laser processing machine Configuration diagram of conventional gas laser oscillator

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated, referring drawings.

(Embodiment)
FIG. 1 shows an embodiment of the present invention. In this figure, 1 is a discharge tube made of a dielectric material such as glass, 2 and 3 are electrodes provided around the discharge tube, 4 is a power source connected to the electrode, 5 is the electrode 2, A discharge space in the discharge tube 1 sandwiched between 3, 6 is a final mirror which is almost totally reflected, 7 is an output mirror which is partially reflected, and the total reflection mirror 6 and the partial reflection mirror 7 are the discharge space 5 are fixedly arranged at both ends to form an optical resonator. Reference numeral 8 denotes a laser beam output from the partial reflection mirror 7.

  The arrow 9 indicates the direction in which the laser gas flows, and it circulates in the axial flow type gas laser oscillator at a pressure of about 100 to 200 Torr. Reference numeral 10 denotes a laser gas flow path, reference numerals 11 and 12 denote heat exchangers for lowering the temperature of the laser gas whose temperature has been increased by discharge in the discharge space 5 and operation of the blower, and reference numeral 13 denotes a blower for circulating the laser gas. Thus, a gas flow of about 100 m / sec is obtained in the discharge space 5. The laser gas flow path 10 and the discharge tube 1 are connected by a laser gas introduction part 14.

  The output mirror 6 and the final stage mirror 7 are fixed to a holder 16 having an angle adjusting mechanism, and are connected to the discharge space by a pipe 18. The holder 16 performs angle adjustment called alignment for amplifying the laser output, and faces the optical axis 15 perpendicularly and parallel to each other, thereby obtaining the maximum laser output.

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

  The laser gas sent out from the blower 13 passes through the laser gas flow path 10 and is introduced into the discharge tube 1 from the laser gas introduction unit 14. In this state, a discharge is generated in the discharge space 5 from the electrodes 2 and 3 connected to the power source 4.

  The laser gas in the discharge space 5 is excited by obtaining this discharge energy, and the excited laser gas is brought into a resonance state by an optical resonator formed by the total reflection mirror 6 and the partial reflection mirror 7. Beam 8 is output. This laser beam 8 is used for applications such as laser processing represented by cutting and welding.

  The discharge tube 1 is disposed along the optical axis 15 of the optical resonator formed by the total reflection mirror 6 and the partial reflection mirror 7, and the discharge tube 1 is held by a discharge tube fixing holder 19.

  As shown in FIG. 2, a spacer 17 is connected to the holder 16 having an angle adjusting mechanism, and a groove for preventing scattered light 21 is provided on the inner spacer surface 20.

  The groove suppresses the scattered light 21. The groove is attached to the holder 16 having the angle adjusting mechanism, and is not affected by the angle adjustment by the alignment. Therefore, the scattered light 21 is suppressed without shifting the incident angle of the scattered light. Can do.

  As shown in FIG. 3, it is theoretically desirable that the inclination angle of the groove for preventing scattered light 21 with respect to the optical axis direction is an acute angle. In the present embodiment, the inclination angle is an acute angle. However, since the depth is required as the inclination angle becomes acute, 15 to 45 degrees are most preferable in terms of the component configuration.

  It is more effective to use aluminum as the spacer material and to deposit carbon having a thickness of 10 μm or more on the surface. This is considered to play a role of preventing reflected light from being absorbed as much as possible and returning to the resonance space. If the deposited film thickness is less than 10 μm, the effect is reduced due to the diffraction phenomenon.

  The spacer material is also effective with ceramic. This is because the ceramic itself has a high absorptance of laser light, so that the scattered light is effectively absorbed.

  The effect of the groove for suppressing the scattered light 21 increases as the output increases. As the amplification of light in the optical resonance space increases, the internal energy increases. Accordingly, the amount of scattered light generated by the diffraction existing therein increases.

  FIG. 4 shows the amount of incident laser light and the amount of scattered light 21. In order to confirm the mode shape, it is common to take a burn pattern that irradiates laser light to acrylic or the like. Normally, this mode shape has a shape like a normal distribution, and it is desirable that there is no inclination or fringe.

  When the scattered light 21 increases, it appears remarkably in the mode shape, and wrinkles such as fringes are generated. The present embodiment has a function of reliably attenuating the scattered light 21 that has not been able to be obtained so far because the scattered light suppressing spacer 17 is attached to the angle adjusting mechanism.

  The gas laser oscillation device and the gas laser processing machine according to the present invention can suppress scattered light without being affected by the angle adjustment by the alignment, so that a high-quality beam mode can be obtained. And it is useful as a gas laser processing machine.

DESCRIPTION OF SYMBOLS 1 Discharge tube 2 Electrode 3 Electrode 4 Power supply 5 Discharge space 6 Total reflection mirror 7 Partial reflection mirror 8 Laser beam 9 Laser gas flow direction 10 Laser gas flow path 11 Heat exchanger 12 Heat exchanger 13 Blower 14 Laser gas introduction part 15 Optical axis 16 Holder 17 Spacer 18 Pipe 19 Discharge tube fixing holder 20 Spacer inner surface 21 Scattered light

Claims (6)

A plurality of discharge means for generating a laser beam by exciting the laser medium to discharge, a pair of optical means disposed on the optical axis of the plurality of discharge means, and a blowing means for circulating the laser medium, A gas laser oscillation apparatus in which an antireflection groove is provided in the angle adjustment mechanism. 2. The gas laser oscillation device according to claim 1, wherein the reflection preventing means groove has an acute inclination angle. The gas laser oscillation apparatus according to claim 1, wherein a material of the groove of the antireflection means is a light absorbing material. The gas laser oscillation device according to any one of claims 1 to 3, wherein a material of the groove of the antireflection means is made of aluminum. The gas laser oscillation apparatus according to claim 4, wherein carbon is attached to a surface of the groove of the antireflection means. 5. The gas laser oscillation apparatus according to claim 1, wherein the antireflection means is made of ceramic.

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