JPS62174985A - High-frequency excitation gas laser - Google Patents

Abstract

PURPOSE:To contrive the enhancement of output by providing ballast condensors separated from split electrodes between the split electrodes composing the electrodes on one side and a high-frequency power source. CONSTITUTION:Condensors 32 of such structure that is proof against application of a high-level discharge retaining voltage are arranged outside a laser tube 20 and are connected between split electrodes 31 and a high-frequency power source 13. When a high frequency is applied between electrodes 30 and 30' from the high-frequency power source 13, a laser gas flowing in the laser tube 30 is excited. The discharge between the split electrodes 30 and 30' of electrodes 30 and 30' is made uniform by the ballast function of ballast condensors 32 and 32' of the electrodes 30 and 30' and the discharge is effected steadily. The ballast condensors 32 and 32' have good voltage-withstanding characteristics and even if a discharge current of higher level than a discharge input level in a conventional device in which an iron tube 11 is coated with a lining layer 12, defects such as insulation damage are not produced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to gas lasers, and more particularly to high frequency excited gas lasers capable of increasing the discharge input level.

High-frequency excited gas lasers are particularly suitable for CO2 lasers, which have high chemical reactivity because (i) the electrodes are arranged outside the laser tube because the electrodes do not come into contact with the laser gas, and (i) they are energy efficient because they are reactive ballasts. is good, (i
ii > Since the voltage is low due to longitudinal discharge, the power supply can be made into a solid-state element, and the discharge uniformity during high-speed gas flow is good, so it is compact, highly efficient, and has a good beam mode, making it suitable for cutting, etc. It is suitable for CO2 laser. A dielectric material that consumes less power than a ballast resistor is used as a ballast to make the discharge uniform. That is, as shown in FIGS. 6 and 7, the electrode 10 of the conventional high-frequency excited CO2 laser is made by coating the surface of an iron pipe 11 with a glass lining layer 12 as a ballast dielectric film. A high frequency from a high frequency power supply 13 is applied to the ffi#A11 to excite the laser gas in a laser tube (not shown) surrounding the ffi#A10. The discharge sustaining voltage of the laser is 5 to 10 KV, and the same voltage is applied to the lining layer 12. On the other hand, since the lining layer 12 is coated on the iron pipe 11, the material for forming the layer 12 should be one that has good adhesion to the iron pipe 11 and has thermal characteristics that match those of the iron pipe 11 so that it will not peel off from the iron pipe 11 during thermal expansion. used.

Here, if the thickness of the lining layer 12 is d, the current density is i, the dielectric constant is ε1, the frequency is ω, and the discharge sustaining voltage is V, then the thickness d of the lining layer 12 is equal to Vεω/i. The thickness is usually set to a value of 0.8 to 1.2 mm.

However, the internal electric field strength E(-i/εω) of the layer 12 is proportional to the current density i, and as the current is increased, dielectric breakdown occurs, so there is a restriction on the discharge input level per unit volume. In addition, since the lining layer 12 is coated, pinholes are likely to occur in the lining layer 12 during manufacturing, and it is also easy to peel off, and in this case, the current flows in a concentrated manner.
From this point of view as well, conventional electrode configurations have limitations on the discharge input level, and the laser output is limited to 1KW. Also,
Conventional electrode spacing was 40H or more, so high quality TEM
Could not get oo mode.

Problems to be Solved by the Invention The present invention aims to provide a high-frequency excited gas laser that can increase the discharge input level per unit volume while combining the advantages of high-frequency excited lasers, and can increase the output of the laser. purpose.

Means for Solving the Problems The present invention provides a high-frequency excited gas laser comprising a pair of electrodes connected to a high-frequency power source, in which at least one of the electrodes is composed of a large number of divided electrodes, and each divided electrode and the It has a configuration including a ballast capacitor interposed between the high frequency power sources and separate from each of the divided electrodes.

Operation When high frequency is applied to the electrodes from a high frequency power source, the laser gas between the electrodes is excited. The discharge between the divided electrodes is made uniform by the ballast action of each ballast capacitor interposed between each of the plurality of divided electrodes constituting at least one of the electrodes and the high frequency power source. Moreover, since each ballast capacitor is provided separately from the divided electrodes, it is possible to use a structure that can withstand the application of high-level discharge sustaining voltages, increasing the discharge input level per unit volume to the electrodes. , contributes to increasing the power of gas lasers.

Embodiment FIGS. 1 and 2 show a high-frequency excitation gas laser according to an embodiment of the present invention. A pair of electric currents 1f130.30' is provided in a laser tube 20 filled with laser gas so that it can freely flow in and out.
are arranged facing each other.

As shown in FIG. 2, a large number of metal divided electrodes 31 are arranged in a two-dimensional array along the inner peripheral surface of one half of the laser tube 20, and each Split electrode 31
The ballast capacitor 32 corresponds to the electrode 31 and is separate from the electrode 31. Each capacitor 32 has a structure that can withstand the application of a high-level discharge sustaining voltage. There is. Further, an electrode 30' along the inner circumferential surface on the other side of the laser tube 20 has the same configuration as the electrode 30, and includes a divided electrode 31' and a ballast capacitor 32'.

The operation of the gas radar having the above configuration will be explained.

When a high frequency is applied between the high frequency power source 13 and the power source 4430.30', the laser gas flowing inside the laser tube 20 is excited. Each electrode 30.30' is ballasted by the ballast capacitor 32.32' of the electrode 30.30'
The discharge between the divided electrodes 31 and 31' is made uniform, and the discharge is performed stably. Capacitor 32.3 for each ballast
2' has good withstand voltage characteristics and has a lining layer 1 on the iron pipe 11.
Even if a discharge current of a higher level than the discharge input level of the conventional device coated with No. 2 is input, problems such as dielectric breakdown will not occur.

FIG. 3 shows a modification of the apparatus shown in FIG. 1, in which the electrode 30 of FIG. The device is composed of an electrode 30''.The operation of the device is substantially the same as that of the above embodiment, so a description thereof will be omitted.

FIGS. 4 and 5 show a gas laser according to a second embodiment of the present invention, and this embodiment differs from the above-mentioned point in that contact between the electrode and the laser gas is prevented and the discharge is further made uniform. This is different from the first embodiment.

That is, a cylindrical case 40 is formed integrally with the side wall of one half of the laser tube 20 to house each divided electrode 31 in isolation from the laser gas inside the laser tube 20.
Each cylindrical case 40 includes a cylindrical portion 41 that is open on the outside, and a lid portion 42 that is welded to the cylindrical portion 41 after housing the divided electrode 31 and closes the opening. At least the inner end wall of the cylindrical portion 41 is connected to the laser tube 20 with respect to the segmented electrode 31.
is disposed facing the electrode 31 on the radially inner position of the
The dielectric ballast 43 is made of 0a), and the voltage drop within the ballast is made sufficiently small. The accommodating portion of the divided electrode 31 in the cylindrical case 40 may remain hollow, but is preferably filled with an electrically conductive or thermally conductive paste.

The operation of this embodiment is basically the same as that of FIGS. 1 to 3, but the divided electrode 3
1 is isolated from the laser gas flowing through the laser tube 20 by the case 40, so it does not come into contact with the laser plasma and is therefore particularly suitable as an electrode for highly chemically reactive CO2 lasers. In addition, ballast capacitor 3
The ballast action of 2 equalizes the discharge between the divided electrodes 31 as described above, and the dielectric ballast 43 equalizes the current density on the surface of each divided electrode 31. Since there is a drift of ionized ions in the laser plasma, there is no large change in impedance, and the discharge on the surface of each electrode 31 becomes uniform. Since the uniformity of the discharge on the surface of each divided electrode 31 is improved in this way, even when the distance between the divided electrodes 31 is increased compared to the case of the first embodiment, the uniformity of the discharge is not so much. It doesn't get worse.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, in a high frequency excited gas laser comprising an electrode connected to a high frequency power source,
Since a ballast capacitor having a structure that can withstand the application of a high-level filtration sustaining voltage is interposed between a large number of divided electrodes constituting at least one of the electrodes and the high-frequency power source, the advantages of the high-frequency excitation laser can be enjoyed. The discharge input level per unit volume can be increased, the laser output can be increased to more than IKW, and if the co-container is made small in diameter, DC
The TEM00 mode similar to the pumped coaxial CO2 laser becomes possible, and it becomes possible to provide a processing laser comparable to the DC pumped coaxial CO2 laser.

[Brief explanation of drawings]

1 and 2 are a partial schematic configuration diagram showing a high-frequency excited gas laser electrode according to a first embodiment of the present invention and a partial plan view showing an arrangement of divided electrodes, and FIG. 3 is a partial plan view showing an arrangement of divided electrodes. FIGS. 4 and 5 are partial schematic configuration diagrams showing a laser according to a modified example; FIGS. 4 and 5 are partial schematic configuration diagrams showing a laser according to a second embodiment of the present invention; and FIGS. A partial perspective view showing a formed state, and FIGS. 6 and 7 are partial schematic configuration diagrams showing a conventional laser. 13...High frequency power supply, 20...Laser tube, 30°30', 30''-Ifffl, 31.31'...
Min ZI TiK, 32.32'...Ballast capacitor, 40...Cylindrical case, 43...Dielectric ballast.

Claims (3)

[Claims] (1) In a high-frequency excited gas laser comprising a pair of electrodes connected to a high-frequency power source, at least one of the electrodes is composed of a large number of divided electrodes, and each divided electrode is interposed between each divided electrode and the high-frequency power source. High frequency excited gas laser with electrodes and separate ballast capacitor. (2) The high-frequency excited gas laser according to claim 1, wherein each of the divided electrodes is covered with a case, and at least the surface of the case facing the other electrode is made of dielectric ballast. (3) The high-frequency excited gas laser according to claim 2, wherein the case is provided integrally with a laser tube, and each of the divided electrodes is arranged outside the laser tube.