JPS60107878A - Gas flow type gas laser tube - Google Patents

Abstract

PURPOSE:To enable the titled laser tube to generate a larger output per unit gain length and to achieve a comparatively small oscillating mode, which is the optimum for processing, by a method wherein discharge plates are arranged in the laser tube at prescribed intervals in the direction of the laser optical axis and a discharge path and a gas flow path are formed. CONSTITUTION:Plural sheets of discharge plates 13 are superposed on each other at prescribed intervals in the direction of a laser optical axis 11 for forming a discharge path 12 and the discharge plates 13 are installed on the enclosing tube 19 of the laser tube. Each of the discharge plates 13 has a hole 21 for a discharge path and plural gas flow holes 22, and the holes 22 are provided at a gas flow hole part 23 only on one side of a straight line 24, which passes through the center of the hole 21. The discharge plates 13 are superposed upon each other in such a way that the holes 21 are superposed upon each other in a straight line with an axis 25 as the center and the hole parts 23 are not superposed on the axis 25. The axis 25 coincides with the optical axis 11. During the operating time of the gas flow type gas laser tube constituted in such a way, discharge is being made to generate between electrodes 15 and 16 through the holes 21 while gas laser is being made to continuously enter from an inlet 17 and to continuously exhaust from an outlet 18.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas flow type gas laser tube that constantly flows laser gas in the direction of the laser optical axis in order to obtain high laser output.

Carbon dioxide gas (00,) In a laser, C
Since O□ decomposes and the laser output decreases, C is added to 5.
A laser gas containing CO (generally a mixed gas of He, N2, and CO2) is flowed into the discharge space to remove decomposed products of CO□ out of the discharge space, thereby preventing a decrease in laser output. Generally, in a C02 laser, a large laser output can be obtained because the temperature of the laser gas in the discharge space is low.

Currently, the most commonly used CO□ laser is a low-speed flow type CO laser using a glass laser tube. In this type of CO2 laser, 100. The laser gas is always flowed at a low speed to prevent the laser output from decreasing due to decomposition. TFC In this type of CO2 laser, a jacket of cooling fluid (water, oil, etc.) is provided outside the glass laser tube to cool the laser gas in order to lower the temperature of the laser gas.

However, the laser output of a low-speed flow type CO2 laser is
7 per meter of gain length due to insufficient removal of CO2 decomposition products and insufficient cooling of the laser gas.
5". Therefore, if you want to obtain a laser output of t kW, you will need a gain length of 1a4" and the device will be very large. L/-4# "The reason why it is most often put into practical use is that it is easy to obtain the optimal oscillation mode for laser processing in low-speed flow type CO lasers.

The purpose of the present invention is to provide a laser oscillation mode that does not increase the temperature of the laser gas, has a small proportion of CO The object of the present invention is to provide a relatively small gas flow type CO□ laser tube that provides the following.

The present invention will be described in detail below using the drawings.

First, for comparison with the present invention, the conventional low-speed flow type 00
A schematic diagram of a two-laser tube is shown in FIG. In the 002 laser of FIG. 1, m 00. To prevent a decrease in laser output due to decomposition, the gas outlet 8 is connected from the gas lower part in the direction of the optical axis 1.
While flowing laser gas at a low speed, a discharge is generated in the discharge space 2 between the discharge electrodes 5 and 6 to obtain laser gain.

In CO lasers, generally the lower the temperature of the laser gas, the greater the laser output can be obtained, so the laser gas must be cooled. In the slow flow type CO□ laser shown in FIG. 1, a cooling fluid jacket 4 surrounding the discharge space 2 is provided to cool the laser gas through the discharge tube wall 3. Cooling fluid is introduced into the cooling fluid jacket 4 from a cooling fluid port 9, and is constantly flowing out from a cooling fluid outlet lO. Cooling fluids are typically water and oil. In this case, as mentioned above, the laser gas is cooled only through the discharge tube wall 3 by the cooling fluid flowing through the cooling fluid jacket 4, so the temperature of the laser gas does not decrease, and the temperature of the laser gas does not decrease. Since the removal of the particles is not sufficient, a laser output of only 75'/m can be expected.

However, in the case of a low-speed flow type CO laser, the laser oscillation mode is limited by the wall of the discharge tube, so the TEMoo mode, which is optimal for laser processing, can be easily obtained.

FIG. 2 shows an embodiment of the present invention. In the 002 laser tube of the present invention, a plurality of discharge plates 13 are stacked at predetermined intervals in the direction of the laser optical axis 11 to form a discharge path 12, and are installed in the laser tube outer tube 19. As shown in FIG. 3, the discharge plate 13 has a discharge path hole 21 and a plurality of gas holes 2.
Has 2. The gas flow hole 22 is straight through the center of the discharge path hole 21! Gas 70 on one side of 24 is provided only in the hole 23. As shown in FIG. 4, the discharge plates 130 are stacked so that the discharge path holes 21 overlap in a straight line around the shaft 25 and the gas flow holes 23 do not overlap.

This is to cause the gas flowing around the discharge space to flow in a spiral pattern and to constantly replace the gas within the discharge space. Further, the size of the gas flow hole is set so that the impedance is larger than that of the discharge path hole, and discharge occurs in the discharge path hole. Note that axis 2 in Figure 4
5 coincides with the laser optical axis in FIG.

00 in Figure 2. In the laser, laser gas is continuously introduced into the gas population 17, and while the gas is discharged from the gas outlet 18, a discharge is generated between the discharge electrodes 15 and 16 through the discharge path hole 21 to obtain laser gain. .

The conventional 00. In the laser tube, all the particles of laser gas flowing through the laser tube are heated, and CO2
The decomposed products remain in the discharge space until they are removed outside the laser tube. However, in the case of Fig. 2, if the flow velocity of the laser gas is the same as in Fig. 1, the c of the gas flowing through the laser tube is
d/(Od+0+r) t, discharge (Od+Of)←
Not present in the hand discharge path. Further, since the excited gas is constantly replaced with surrounding gas, decomposed products are quickly removed from the discharge space. ζ Here, Od is the discharge path hole 21
The gas flow conductance, Cf, is the sum of the conductances of the plurality of gas flow holes 22.

Therefore, as in FIG.
If cooling fluid is flowed into the discharge space, the temperature of the laser gas will be lower in the case of Fig. 2 than in the case of Fig. 1.
Since the amount of the decomposition product No. 2 is small, a large laser output can be obtained.

Note that the discharge plate 13 is mainly made of a material with high thermal conductivity, that is, an insulator such as BN, Bed, A/, O8, carbon graphite, or a metal such as Ou or W. Since the oscillation mode of the laser tube shown in FIG. 2 is limited by the diameter of the discharge path hole 21, the oscillation mode TEMoo mode, which is optimal for laser processing, can be obtained as in FIG. 1.

By the way, in the laser tube shown in FIG. 2, a characteristic laser gas cooling method can be considered. Figure 5 shows the case where an assembly rod 26 is used when stacking discharge circuit boards.
If 6 is made into a tube and a cooling fluid is allowed to flow inside, the laser gas can be cooled more efficiently than in the embodiment shown in FIG. 2, and a larger laser output can be obtained. Of course, the cooling methods shown in FIG.

In addition, in the above embodiment, the gas flow opening was a hole, but
A notch may be used as shown in FIG.

Further, as shown in FIG. 7, the discharge path opening and the gas flow opening may be connected. The point is that the discharge only needs to occur at the opening for the discharge path.

As described in detail above, if the present invention is used, the discharge plate having a discharge path opening and a plurality of gas flow openings each having a smaller area than the discharge path opening can be arranged at regular intervals. , the discharge path and the gas flow path are formed by arranging them in the laser optical axis direction so that the discharge path openings overlap in a straight line centering on the laser optical axis, and so that the gas flow openings of adjacent discharge plates do not overlap. As a result, the large laser power is TE
A gas flow type CO□ laser tube obtained in Moo mode is obtained.

The above explanation is based on 00. Although it is limited to lasers,
It is clear that the present invention can also be applied to O2 lasers, N02 lasers, and the like.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a conventional low-speed 70-type CO2 laser tube. 1... Laser optical axis, 2... Discharge space, 3... Discharge tube wall. 4...Cooling fluid jacket), 5.6...Electrode, 7...
・Laser gas inlet, 8...Laser gas outlet. 9... Cooling fluid inlet, 10... Cooling fluid outlet. Fig. 2 is a diagram showing an embodiment of the present invention, Fig. 3, Fig. 6,
81￥7 Figure is a diagram showing an example of the discharge plate used in the present invention,
FIGS. 4 and 5 are diagrams showing the arrangement of discharge plates. 11... Laser optical axis, 12... Discharge path, 13...
Discharge plate, 114...cooling fluid jack), 15.16
...discharge electrode. I7...Laser gas population, 18...Laser gas outlet. 19... Laser tube wall, 21... Opening for discharge path. 22...Gas 70-1 opening, 23...Gas 70-
24 - A straight line passing through the center of the opening for the discharge path. 25... shaft, 26... assembly rod. Figure 1 Figure 2 Figure 5 75 Figure 6 3 Figure 6 Off view

Claims (1)

[Claims] A gas laser tube in which laser gas is constantly flowed in the direction of the laser optical axis has an opening for a discharge path, and the opening for the discharge path also has a small opening area or a plurality of gas flow openings. A plurality of discharge plates are arranged so that the discharge path openings of the discharge plates are aligned in a straight line with the laser optical axis as the center, and the gas flow openings of adjacent discharge plates do not overlap. A gas 70-type gas laser tube characterized in that a discharge path and a gas flow path are arranged in the laser tube at predetermined intervals in the direction of the gas laser tube.