JP2983570B2 - Laser oscillator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a laser oscillator.

(Prior Art) Conventionally, CO ₂ discharge excitation laser oscillator as the laser oscillator, in addition to He of CO _2, and discharges in a laser containing a N ₂ gas, and excite the CO ₂ molecules efficiently. This CO ₂
The molecules are partially dissociated into CO and O by the discharge energy. As a result, the number of excited CO ₂ molecules decreases, and the laser output decreases.

In addition, discharge energy is given to the dissociated molecules, but the output efficiency is reduced because the excitation is not related to the laser output. Furthermore, the dissociated O becomes an anion due to electron attachment, which makes the glow discharge unstable and causes an arc discharge in which a large current is locally generated, but this arc tends to cause the dissociation of CO ₂ electrons. .

This dissociation occurs more frequently as the discharge power density increases. For example, in a high-output laser oscillator of 100 W or more, a new laser gas is introduced to prevent a decrease in output due to the dissociation. Since the gas pressure of the laser gas needs to be kept constant, a part of the laser gas in the laser container is exhausted to the outside of the laser container by a vacuum pump at the same time as the inflow. Therefore, gas exchange of the laser gas is performed as needed.

Further, in another CO ₂ laser oscillator, the dissociation of CO ₂ is a reversible reaction of _{CO 2 CO + 1/20 2} , although the leftward reaction rate is slow, use platinum as a catalyst, CO oxidation At higher speeds, the overall dissociation of CO ₂ is suppressed and the operation is performed without gas exchange.

(Problems to be Solved by the Invention) Among the above-mentioned conventional techniques, the former laser oscillator for exchanging the laser gas has a problem that the gas consumption increases and the running cost increases. That is, the gas consumption is, for example, 50
0.5 to 3 / min (1 day: 8 hours operation)
Therefore, 240 to 1440 are used per day. In addition, if a laser oscillator is equipped with a gas recycler, gas consumption will be reduced, but gas recyclers are expensive and have little effect. Gas recyclers cannot be used.

On the other hand, in the latter laser oscillator that does not exchange laser gas using a platinum catalyst, platinum as a catalyst has little effect at room temperature, and a part of the laser gas in the laser container is circulated by a pump, and this laser gas is heated by a heater. It is necessary to heat at, pass through a platinum catalyst and return to the laser container again. This system is effective when the laser container is small because the amount of laser gas passing per hour is small, but it is ineffective when the laser container is large, and the device itself becomes complicated and very expensive. There was a problem of becoming.

(Means for Solving the Problems) In view of the above problems, the present invention provides a metal mesh tube in which a room temperature gold catalyst is sealed in a circulation path for circulating a laser gas in a laser vessel in a laser oscillator. Spirally provided along the longitudinal direction of the circulation path,
The spiral portion of the metal mesh tube has a large-diameter portion in contact with the inner wall of the circulation path and a non-contact small-diameter portion.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 5, for example, an axial-flow type CO ₂ laser oscillator 1 as a laser oscillator includes a laser tube 3 made of a glass tube for performing resonance amplification of excitation light, and an H 2.
A laser gas circulator 5 for supplying and circulating a laser gas in which e, N ₂ , and CO ₂ are mixed at an appropriate ratio to the laser tube 3 and the like.

In the laser tube 3, a plurality of anodes 7 and cathodes 9, which are electrodes for performing discharge, are arranged at appropriate positions, and a total reflection mirror 1 and an output mirror 13 are provided at the ends.
Is installed.

In order to generate a discharge between the anode 7 and the cathode 9, the anode 7 and the cathode 9 are connected to a high-voltage power supply.
15 connected to a high voltage power supply circuit.

The laser gas circulation device 5 includes first and second heat exchangers 17, 19 for cooling the laser gas from the laser tube 3.
And a roots blower 21 for supplying a laser gas to the laser tube 3. The laser tube 3 is connected to the laser tube 3 via a gas return path 23 and a gas supply path 25. In addition, the gas return path 23 is formed by connecting a glass tube 27 and a metal tube 29, for example, and the gas supply path 25 is formed by connecting a glass tube 31 and a metal tube 33, for example. Further, a supply pipe 35 for supplying cooling water and a discharge pipe 37 for discharging used cooling water are connected to the first and second heat exchangers 17 and 19.

With the above configuration, the Roots blower 21 is driven to circulate the laser gas, and a high voltage is applied between the anode 7 and the cathode 9 by a high voltage power supply circuit having a high voltage power supply 15 so that the anode 7 and the cathode 9 By performing the discharge in the interval, the laser light is output from the output mirror 13 side.

A room temperature gold catalyst is provided in a part 27A of the glass tube 27 in the gas return path 23. More specifically, as shown in FIG. _1, the inner diameter of the glass tube 27 is set to, for example, l ₁ to 2.
In the case of 5 l ₁ , a spiral metal mesh tube 41 such as brass enclosing a room temperature gold catalyst 39 is provided in the glass tube 27 along the longitudinal direction of the glass tube 27. The length of the metal mesh tube 41 in the longitudinal direction is 5 l ₁ , the pitch of the large diameter portion is 3 l ₁ and the spiral pitch is 1
/ 2l ₁ and gradually become smaller in diameter.
Moreover, the metal mesh tubes 41 in the portion of the large diameter portion of the pitch 3l ₁ is provided in contact with the inner wall of the glass tube 27.
Thus, the laser gas flow does not become too much resistance (less resistance), and the laser gas flow near the inner wall and the center of the glass tube 27 comes into contact with the room temperature catalyst 39 and passes.

The shape of the mesh in metal mesh tubes 41, for example interval has a 1 / 20l ₁ about reticulated. As shown in FIG. 2, the room-temperature gold catalyst 39 is formed on the outer peripheral surface of a sphere 39A made of Al ₂ O ₃ (alumina ceramics).
(〜40 Aφ) It is preferable that the catalyst sphere (diameter: about 3/40 l ₁ ) to which 39B is adhered.

Therefore, when the laser gas passes through the room temperature gold catalyst 39 sealed in the metal mesh tube 41,
Dissociated CO, O is become the reaction of _{CO + 1/20 1 → CO} 2 occurs per the normal temperature metal catalyst 39.

Since the mesh of the metal mesh tube 41 is metal, the glass tube 27 separated from the (−) high voltage anode 7 is used.
A, but a part 33A of the metal pipe 33 in the gas supply path 25
You can put it in. However, when it is placed on a part 29B of the glass tube 29 in the gas return path 23, the anode 7 and the metal tube 29
This is not a good place to install the room-temperature gold catalyst 39 because a discharge current may flow to the room temperature.

FIG. 3 shows a reference example. That is, in FIG. 3, when the inner diameter of the glass tube 27 for example, l ₁ ~2.5l _1, Figure 4 along the longitudinal direction of the glass tube 27 in the glass tube 27 (A), (B) glass with an appropriate spacing for example l ₁ is hollow cylindrical Teflon mesh 45 attached to the Teflon sheet 43 made of a cold gold catalyst 39 from a thickness of, for example 1/200 l ₁ of encapsulated length 1 / 2l ₁ as shown in It is mounted on the inner wall of the tube 27.

Therefore, the operation and effect in this case are the same as those shown in FIG.

FIG. 3 shows a part 27B of the glass tube 27.
Can also be placed.

Referring to FIG. 7, a three-axis orthogonal CO ₂ laser oscillator 4
A laser resonator 51 extending in a direction perpendicular to the plane of FIG. 7 is provided in the upper part of the laser oscillator body 49 of FIG. An upper gas passage 53 penetrating in the left-right direction is formed in the laser resonator 51.

Mirrors 55 are attached to left and right side walls of the upper gas passage 53 in the laser gas flow direction. That is, each of the mirrors is provided with a rear folding mirror and a primary mirror on the rear side wall surface of the gas passage 53 in FIG. A mirror is provided.

Therefore, the plurality of mirrors 55
A laser light path 57 is formed as a region sandwiched between the two.

An anode 59 for discharging in the laser gas flow is provided at a lower surface position of the laser light path 57, and a cathode 61 is provided above the anode 59.

Since the laser gas flow was circulated, the laser gas straightening plates 63A and 63B are extended in the left-right direction, and are provided downward. A blower 65 for blowing a laser gas flow is provided below the laser resonator 51 in the laser oscillator body 49.

After the laser gas flow blown by the blower 65 passes through the upper gas passage 53 via the side gas passage 67,
Through another side gas passage 69, it reaches a heat exchanger 71 provided on the right side of the blower 65, and is cooled by the heat exchanger 71.
It is designed to be returned to the blower 65.

Laser gas straightening plate 63B in the side gas passage 69
A room temperature gold catalyst 39 is provided on the inner wall of the. More specifically, as shown in FIGS. 6A and 6B, the room temperature gold catalyst 39 is sealed in a metal mesh bag 73 of, for example, brass. Room temperature gold catalyst in Teflon bag made of Teflon with many small holes instead of metal mesh bag 73
Even if 39 is enclosed, it does not matter.

The mesh shape of the metal mesh bag 73 and the small holes of the Teflon bag may be slightly larger than the size of the catalyst sphere already described in FIG.

Therefore, a metal mesh bag in which the room temperature gold catalyst 39 is enclosed
The operation and effect when the 73 and the Teflon bag are provided on the inner wall of the laser gas straightening plate 63B in the side gas passage 69 in FIG. 7 are the same as those described in FIG.

FIG. 8 shows the results of measuring the laser output when the room-temperature gold catalyst 39 is provided in the circulation path for circulating the laser gas of the laser oscillators 1 and 47 and when the conventional catalyst is not provided. It is shown. In FIG. 8, curve A
In the case of the present embodiment, since the curve B shows the conventional case, the curve A suppresses the time reduction of the laser output as compared with the curve B, and improves the temporal stability of the laser output. be able to.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes.

[Effects of the Invention] As can be understood from the above description of the embodiments, in short, the present invention provides a room-temperature gold catalyst (39) in a circulation path for circulating a laser gas in a laser vessel in a laser oscillator. A sealed metal mesh tube (41) is spirally provided along the longitudinal direction of the circulation path, and a spiral part of the metal mesh tube (41) has a large diameter portion which is in contact with the inner wall of the circulation path. Since it has a configuration with a small diameter portion of contact, the laser gas flowing near the inner wall and near the center of the circulation path contacts the spiral normal temperature gold catalyst 39 and receives the action of the catalyst, so the laser gas divergence is reduced. Is what you can do.

At this time, since the metal mesh tube 41 is formed in a spiral shape and has a large diameter portion and a small diameter portion, the resistance to the laser gas flow is reduced and the turbulence is excited to contact the catalyst. It is effective.

[Brief description of the drawings]

1 shows a main part of the present invention, FIG. 5 is an enlarged view of a part viewed from the arrow I, FIG. 2 is an enlarged view of a part viewed from the arrow II in FIG. 1, FIG. FIG. 4 (A) is a sectional view taken along the line IV-IV in FIG. 3, FIG. 4 (B) is a sectional view in FIG. 4 (A), and FIG. schematic diagram of an axial-flow type CO ₂ laser oscillator, FIG. 6 (a) is an enlarged view of a VI arrow portion in FIG. 7, FIG. 6 (B) is a developed view of a metal mesh bag, FIG. 7 is a FIG. 8 is a front view of another three-axis orthogonal CO ₂ laser oscillator instead of FIG. 1, and FIG. 8 is an explanatory diagram comparing the laser output of the present embodiment with that of the conventional one. 1 ... Axial flow type CO ₂ laser oscillator, 3 ... Laser tube,
5 laser gas 7 anode 9 cathode 23 gas return path
25 Gas supply channel 39 Room temperature gold catalyst 41 Metal mesh tube 41A
… Sphere, 41B… Au 43… Teflon sheet, 45… mesh, 47… 3-axis orthogonal laser oscillator 53… upper gas passage, 59… anode, 61… cathode 67, 69… side Gas passage, 73 ... Metal mesh bag

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-308983 (JP, A) JP-A-60-113490 (JP, A) JP-A-50-64163 (JP, A) JP-A-54-163 60589 (JP, A) JP-A-62-247839 (JP, A) JP-A-2-161787 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01S 3 / 03,3 / 097 B01J 23 / 52,35 / 08

Claims (1)

(57) [Claims] 1. A metal mesh tube (41) enclosing a room temperature gold catalyst (39) is spirally wound along a longitudinal direction of a circulation path in a circulation path for circulating a laser gas in a laser vessel of a laser oscillator. And a spiral portion of the metal mesh tube (41) having a large-diameter portion in contact with an inner wall of the circulation path and a non-contact small-diameter portion.