JP3139103B2 - Axial 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 an axial-flow laser oscillator having a stabilized laser output used in a laser cutting machine or the like and having a reduced size.

[0002]

2. Description of the Related Art A conventional axial flow laser oscillator will be described below. In FIG. 3, 1 is a resonator base, 1a,
1b is a resonator holding plate, 2 is an output mirror, 3 is a total reflection mirror, 4 is a folding mirror, 5a to 5d are discharge tubes, 6 is a blower, and 7a to
7c is an air supply duct, 9a and 9b are distribution blocks, 25a
Is an assembly block, 25b and 25c are assembly block support portions, 26 is an exhaust duct, 27 is a gas cooler, 28 is an exhaust duct, 29 is a heat exchanger, and 30a to 30c are cooling fans.

[0003] The relationship between the components and the operation of the axial flow laser oscillator comprising the above components will be described. FIG.
As shown in FIG.
a, 1b, and an output mirror 2, a total reflection mirror 3, a folding mirror 4, and discharge tubes 5a to 5d are arranged coaxially.
The gas laser medium is supplied by a blower 6 to supply air ducts 7a to 7c.
From the distribution block 9 attached to the resonator holding plates 1a, 1b
The laser light is supplied equally to the four discharge tubes 5a to 5d through a and 9b, and is excited by discharge by a discharge electrode to which a high voltage generated by a high-voltage power supply (not shown) is applied to output laser light. The gas laser medium, which has been discharged and heated by passing through the discharge tubes 5a to 5d, is collected by the collective block 25a held by the collective block supports 25b and 25c at the center of the resonator.
It is collected in a book and exhausted from the exhaust duct 26. The exhausted gas laser medium is cooled by the gas cooler 27 connected to the exhaust duct 26, and then returned to the blower 6 through the exhaust duct 28. The atmosphere in the oscillator is cooled by the heat exchanger 29 and the cooling fans 30a to 30c.

A fin tube type heat exchanger generally used for gas cooling of this kind of axial flow type laser oscillator comprises a fin tube core for performing heat exchange and a casing for accommodating the core, and is heated. The gas laser medium is connected to a casing of a gas cooler mounted separately from a laser resonator through a pipe for collecting and exhausting the gas laser medium.

[0005] In a conventional axial-flow laser oscillator, a heated gas laser medium is placed on an assembly block 25 on an optical axis.
When the oscillator is started to heat the exhaust duct 26 connecting the gas cooler 27 and the collecting block 25, or when the discharge input is changed to adjust the laser output, the expansion due to the temperature change of these pipes. Shrinkage occurs. Also,
Since the surface temperature has risen, the resonator base 1 is also warmed by radiant heat, and the temperature distribution of the resonator base 1 becomes uneven.

Further, since the respective joints of the discharge tube 5, the collecting block 25, and the exhaust duct 26 are exposed to the high-temperature gas laser medium, deterioration of the pipe seal easily occurs.

[0007]

As described above, the conventional structure has a problem that the optical axis of the resonator is disturbed and the output fluctuates due to expansion and contraction of each pipe and non-uniform temperature distribution of the resonator base 1. In addition, there is a problem that the airtightness between the gas laser medium and the air is deteriorated due to deterioration of a pipe seal at a joint portion of each pipe, and the laser output is reduced. The above problem may be mitigated by blowing cool air to the collecting block 25 and the exhaust duct 26 with the fan 30 of the above. However, it is not possible to sufficiently suppress the optical axis of the resonator, and the heat exchanger 29 For this reason, there was a problem that the shape was enlarged.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an axial-flow laser oscillator having a stabilized laser output and a reduced size.

[0009]

SUMMARY OF THE INVENTION To achieve this object, an axial-flow laser oscillator according to the present invention comprises a cooling medium, a gas laser medium, and a cooling medium provided in a gap between a plurality of stacked plates which are kept airtight. A gas cooler in which a plurality of media and an atmosphere in an oscillator are circulated in order as a set, a gas cooler in which a plurality of sets are stacked, and a discharge tube coaxial with the optical axis of the laser resonator from both surfaces of the stacked plates of the gas cooler. It has a discharge tube provided with holes through which the same number of laser beams pass, and an exhaust duct provided in a hole provided in the gas cooler at a position away from the discharge tubes.

[0010]

With this configuration, the gas laser medium heated by discharge excitation is cooled immediately after exiting the discharge tube, so that the temperature rise in the exhaust duct and the temperature of the resonator base due to radiant heat are eliminated, and the heat of the hermetic seal is reduced. Deterioration will be eliminated.

[0011]

An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2 showing one embodiment of the present invention, the same parts as those of the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 1 and 2, the discharge tube 5a
Alternatively, 5c is attached to the gas distribution block 9a or 9b at one end, and the other end is attached to the through hole formed by the distribution partition tube 19a at the lower part of the gas cooler 10 by the connection flange 5e or 5g, and the discharge tube 5b or 5d. Similarly, the distribution partition tube 19b (not shown, and similarly not shown below)
It is attached to the opened through-hole by a connection flange.

The exhaust duct 8 is connected by a connecting flange 8a.
In addition, the relief pipe 11 is attached to the through-hole portion formed by the collecting partition pipe 19c at the upper part of the gas cooler 10 by the connection flange 11a.

The gas cooler 10 includes mounting fittings 10c, 10
d, fixed on the resonator base 1 and the gas cooler 1
Water inlet 10 at the bottom where cooling water enters and exits on the diagonal of 0
a is provided with a water outlet 10b at the top.

The gas cooler 10 includes an air / water partition plate 15.
a, a set of 15b to 18b and a set of 15c to 18c arranged in the same manner as a set of water / gas laser medium partition plates 16a, 17a and an air / water partition plate 18a with a gap of several mm therebetween.
18c is formed by stacking the discharge tubes 5a,
At the same intervals as the intervals between the discharge tubes 5c and the discharge tubes 5b and 5d, two rows of holes having an inner diameter larger than the diameter of the discharge tubes are opened, and the distribution partition tubes 19a and 19b of the gas laser medium are inserted and bonded.
The distribution partition pipes 19a and 19b are provided with holes only at the positions of the gaps between the water / gas laser medium partition plates 16a to 16c and 17a to 17c.

A through-hole having a cross-sectional area equal to the sum of the cross-sectional areas of the four discharge tubes 5 is formed in the upper portion of the gas cooler 10 between the two distribution partition tubes 19a and 19b. Inserting the partition pipe 19c of the laser medium and inserting each partition plate 15a
~ 15c, 16a ~ 16c, 17a ~ 17c, 18a ~
18c. The collecting partition tube 19c is provided with holes only at the positions of the gaps between the water / gas laser medium partition plates 16a to 16c and 17a to 17c, similarly to the distribution partition tubes 19a and 19b.

An exhaust duct 8 and a relief pipe 11 are connected to holes on both sides of the gas cooler 10 opened by the collecting partition pipe 19c. The other end of the exhaust duct 8 is connected to a blower (not shown), and the other end of the relief pipe 11 is fixed to an oscillator casing (not shown). The cross-sectional areas of the relief pipe 11 and the exhaust duct 8 are equivalent.

The water inlets and outlets at the upper and lower positions of the gas cooler 10 are provided with water distribution partition pipes which are inserted and bonded through the respective partition plates similarly to the distribution partition pipes 19a, 19b and 19c of the gas laser medium. 20a, connected to the collecting partition tube 20b. Air / water partition plates 15a to 15
The gap between 15c and the water / gas laser medium partition 16a-16c and the water / gas laser medium partition 17a-17c
A hole is formed in a gap between the air and water / water partition plates 18a to 18c.

The outer side surfaces 20a, 21 of the gas cooler 10
Although b is adhered to each partition plate on the inner surface, a gap between the air / water partition plates 15a to 15c and 18a to 18c is provided with a strip-shaped hole having substantially the same width as the gap. The blower fan 12 is arranged beside the gas cooler 10.

The operation of the axial-flow laser oscillator configured as described above will be described. Four discharge tubes 5a-
5d, the gas laser medium is supplied by the blower 6 from the air supply ducts 7a to 7c into four equal parts through the distribution blocks 9a and 9b in the same manner as described in the conventional example, and the high voltage generated by the high voltage source is supplied. Glow discharge is caused between the applied discharge electrodes to be excited to oscillate laser light. The oscillated laser light is amplified and reciprocated while being bent by the folding mirror 4 between the output mirror 2 and the total reflection mirror 3, and is finally taken out of the output mirror 2. The gas laser medium whose temperature has risen in the discharge tube 5 is recovered by the gas cooler 10, cooled, and sent again to the discharge tube 5 by the blower 6 through the air supply ducts 7 a to 7 c.

In the gas cooler 10, the distribution partition pipes 19a, 1
9b to water / gas laser medium partition plates 16a to 16c and 1
It flows into the gaps between 7a to 17c and is collected again by the collecting partition pipe 19c, but is indicated by solid arrows along the water / gas laser medium partition plates 16a to 16c and 17a to 17c. As the gas laser medium flows,
Cooling water flows between the air / water partition plates 15a to 15c and the water / gas laser medium partition plates 16a to 16c and between the water / gas laser medium partition plates 17a to 17c and the air / water partition plates 18a to 18c. As shown by the arrow, heat flows through each partition plate due to the temperature difference between the gas laser medium and the cooling water flow, and when the gas laser medium exits to the exhaust duct 8, it is cooled and exits.

The relaxation pipe 11 is moved toward the exhaust duct 8 by the gas cooler 10 with a vacuum force corresponding to the cross-sectional area of the exhaust duct 8.
Counteracts the pulling force.

Further, the blower fan 12 beside the gas cooler 10 is provided with air / water partition plates 18a and 15 in the gas cooler 10.
The atmosphere in the oscillator is caused to flow in the direction perpendicular to the plane of FIG. 2 into the gap between b and 18b and 15c, and the atmosphere in the oscillator is cooled and stabilized by cooling water.

As a result, the exhaust duct 8 is not heated and expanded by the high-temperature gas laser medium exiting the discharge tube 5,
There is no heat radiation from the gas laser medium. Further, since the atmosphere in the oscillator flowing along the gas cooler 10 is cooled by the cooling water, the temperature distribution of the resonator base 1 does not become uneven even if the heat exchanger in the oscillator is not provided. Therefore, the optical axis of the resonator does not deviate during the operation of the oscillator.
Further, a hermetic seal 22 for hermetic sealing with the gas laser medium.
Since the portions b and 22d are in contact with the air / water partition plate 15a and have a low temperature, the hermetic seals 22b and 22d are unlikely to deteriorate.

As described above, according to the present embodiment, a plurality of plates are stacked and air-tight with each other.
A gas laser medium, cooling water, and an atmosphere in the oscillator are sequentially circulated as one set. A gas cooler in which a plurality of sets are stacked, a discharge tube coaxial with the optical axis of the laser resonator, and a discharge tube separated from the discharge tube By providing the exhaust duct at the position set as described above, it is possible to suppress the optical axis of the resonator during laser oscillation from being disordered and to keep the output stable. In addition, the airtight seals 22b and 22d
Since thermal degradation does not occur, output does not decrease due to vacuum leakage, and output can be stabilized for a long time. Furthermore, the shape of the whole oscillator can be reduced because it can be incorporated in the optical axis of the resonator of the gas cooler 10 and the cooling heat exchanger in the oscillator can be dispensed with.

[0026]

As is apparent from the above description of the embodiment, the present invention provides a cooling medium, a gas laser medium, a cooling medium, an oscillator in a gap between a plurality of plates stacked while maintaining airtightness. As a set, a gas cooler in which a plurality of sets are stacked, and the same number of laser beams as the discharge tubes coaxially with the optical axis of the laser oscillator are provided on both surfaces of the stacked plates of the gas cooler. The laser output is stabilized and the shape is small due to the configuration with a discharge tube provided with a hole for circulation and an exhaust duct provided in a hole provided in the gas cooler at a position away from the discharge tube. Thus, an excellent axial flow type laser oscillator can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a concept of a main part of an axial flow laser oscillator according to an embodiment of the present invention.

FIG. 2 is a side view showing a cross section of a coaxial flow laser oscillator with a part of a gas cooler not shown;

FIG. 3 is a schematic perspective view showing a concept of a main part of a conventional axial flow laser oscillator.

[Explanation of symbols]

 5a-5d Discharge tube 6 Blower 7a-7c Air supply duct 8 Exhaust duct 10 Gas cooler

Claims (1)

(57) [Claims] 1. A plurality of discharge tubes having discharge electrodes, a laser resonator having output mirrors and total reflection mirrors attached to both ends thereof, a blower of a gas laser medium, and a power supply connecting the laser resonator and the blower. An axis that includes an air duct and an exhaust duct, a gas cooler, and a high-voltage power supply, and that excites the gas laser medium in the discharge tube by discharge of the discharge electrode connected to the high-voltage power supply to generate laser light. A plurality of flow-type laser oscillators in which a cooling medium, a gas laser medium, a cooling medium, and an atmosphere in an oscillator are sequentially passed through gaps between stacked plates that maintain airtightness. The gas cooler configured by stacking, the discharge tube provided with holes through which the laser light passes coaxially with the optical axis of the laser resonator from both sides of the stacked plates of the gas cooler, Previous An axial-flow laser oscillator including the exhaust duct provided in a hole provided in the gas cooler at a position away from the discharge tube.