JPS6113679A - Gas laser device - Google Patents

Abstract

PURPOSE:To obtain discharge at large power density by mounting a stable auxiliary discharge section on the upstream side of the main discharge of a laser gas, generating plasma and injecting plasma to a main discharge section. CONSTITUTION:A laser gas current 2 flows in a duct 1, and a plurality of electrodes 3 for main discharge are fitted in the duct 1. Ballast capacitances 4 are each connected to these electrodes 3, and the electrodes 3 are connected to an AC power supply 5 through these capacitances 4. Auxiliary discharge electrodes 7 are mounted on the upstream sides of the electrodes 3. Ballast capacitances 8 are connected to the electrodes 7, and connected to a power supply 5 through the capacitances 8. The capacitances 8 are brought to values sufficiently smaller than the capacitances 4 at that time. Discharge currents are limited by the impedance of the capacitance, and do not shift to an arc. When plasma having small density generated in the auxiliary discharge regions is injected to a section, in which main discharge is generated, together with the flow of the gas 1, the electrode drop voltage of the electrodes 3 reduces, and the increase of electric fields in the vicinity of the electrodes 3 is prevented. Accordingly, stable glow is obtained even when current density increases.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a gas laser device, and particularly to a high output gas laser device of IKW or higher.

[Technical background of the invention and its problems]

Conventional high-output gas lasers, particularly those with substantially continuous output, have used DC discharge to excite the laser gas. In order to stabilize DC discharge, the anode or cathode is divided and a discharge stabilizing resistor (parast resistor) is connected to these electrodes. The power consumed by this parast resistor is approximately the same amount as the discharge power input to excite the laser gas, so it significantly reduces the effective efficiency of the laser device.

For this reason, an alternating current discharge method that does not require a parasitic resistor was proposed. FIG. 4 shows an electrode configuration of an AC discharge type that has been proposed in the past. That is, a plurality of discharge electrodes (3) are arranged so that the direction of discharge is perpendicular to the flow direction of the laser gas (2) circulating in the duct (1). Parast capacitors 4 are connected to each of these. AC power supply (discharge power supply) (5) via pallast capacitance (4)
It is connected to the. In addition, in the above configuration, folded resonator mirrors C (not shown) are further provided to face each other so that the optical axis of the laser beam (6) is perpendicular to the flow direction and the discharge direction of the laser gas (1). There is. In the above configuration, there is no power loss in the ballast capacitor (4), so the efficiency of the entire laser device is improved. However, the input power per unit volume was about 5 W/- at the stability limit, which was about the same as that of the DC discharge type, and a discharge with a high power density could not be obtained.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a device that can stably supply power to a laser gas of 5 W/cd or more.

[Summary of the invention]

By providing a stable auxiliary discharge section upstream of the main discharge of the laser gas, generating plasma, and injecting it into the main discharge section, increasing the electric field near the electrodes was prevented.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on drawings showing examples. Components that are the same as those shown in FIG. 4 are designated by the same reference numerals, and detailed explanations will be omitted.

FIG. 1 shows an embodiment of the present invention in which a laser gas flow (2) flows in a duct (1), and a plurality of main discharge electrodes (3) are provided in the duct (1). Each of these electrodes (3) is connected to a parast capacitor (4), and is connected to an AC power source (6) via this parast capacitor (4).

An auxiliary discharge electrode (force) is provided on the upstream side of the main discharge electrode (3). A pallast capacitor (8) is connected to this electrode (force).
)K connected.

Here, the parast capacity (8) is set to a sufficiently small value compared to the main discharge parast capacity (4)K. This impedance limits the discharge current and prevents it from turning into an arc. When the low-density plasma generated in this auxiliary discharge region is carried by the flow of laser gas (1) and injected into the area where the main discharge occurs, the electrode drop voltage of the main discharge electrode (3) decreases and the electric field near the electrode increases. was prevented.

Therefore, it has been found that by using this auxiliary discharge, a stable glow can be obtained even when the current density of the main discharge portion is 2 to 3 times higher than that without the auxiliary discharge.

FIGS. 2 and 3 show other auxiliary discharge types of the present invention. In FIG. 2, the auxiliary discharge electrode On is an electrode whose center portion is made of a conductor a1) and whose peripheral portion is covered with a dielectric material 02. In such an electrode configuration, a so-called silent discharge occurs and a dilute plasma is generated. By placing this plasma on the laser gas (1) and sending it into the main discharge region, it became possible to relax the electric field in the main discharge region and expand the stable discharge region to the larger discharge current region. Discharge electrode (1'3 is a needle electrode with high resistance 0)
It has a configuration in which it is connected to an AC power source (5) via 4.

The main discharge can be stably operated even at high current density by injecting the dilute plasma produced by the corona discharge generated from the tip of the needle electrode into the main discharge electrode area along with the flow of the laser gas (2).

〔Effect of the invention〕

Since the main discharge is an AC discharge, there is no power loss due to ballast resistance in the case of a DC discharge type, and the power efficiency of the device is improved.Moreover, compared to the conventional AC discharge type, the stable region of glow discharge can be reduced to a higher power density. Since it became possible to expand to the side, it became possible to manufacture a large output machine in a small size.

Note that the effects of the present invention do not change even if the shape of the discharge electrodes connected through the capacitance is plate-shaped, bottle-shaped, rod-shaped, or a combination thereof.

The effects of the present invention do not change even if multiple sets of auxiliary discharge sections and main discharge sections are arranged alternately from the upstream side of the gas flow.〇The effects of the present invention do not change even if a plurality of sets of auxiliary discharge sections and main discharge sections are arranged sequentially from the upstream side of the gas flow. The effect of the invention remains the same. The auxiliary discharge section has the effect of stabilizing the main discharge and reducing the firing voltage of the main discharge. Therefore, by separating the main discharge power source and the auxiliary discharge power source, it is possible to reduce the capacity of the main discharge power source. The auxiliary discharge power source may be a pulse power source or a DC power source.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, FIGS. 2 and 3 are schematic diagrams showing other embodiments of the present invention, and FIG. 4 is a schematic diagram showing a conventional example. (1)...Duct, (2)...Laser gas, (3)
... Main discharge electrode, (5) ... AC power supply, (6)
...Laser beam, (force...auxiliary discharge electrode, (4
), (8)...Palast capacity. Agent Patent attorney Kensuke Chika (and 1 other person) Figure 1 Figure 2 Dimensions Bacteria ←

Claims (4)

[Claims] (1) The laser gas flow, the main discharge discharge path, and the laser beam are arranged in a triaxial orthogonal configuration in which each axial direction is substantially orthogonal to each other, and on the upstream side of the main discharge portion in the flow direction of the laser gas flow. An auxiliary discharge device is provided, the main discharge is an alternating current discharge performed through two or more capacities, and the auxiliary discharge by the auxiliary discharge device is performed through a high impedance to the main discharge power source or the auxiliary power source. gas laser equipment. (2) The gas laser device according to claim 1, wherein the auxiliary discharge is performed through a capacitance smaller than the above-mentioned capacitance. (3) The gas laser device according to claim 1, wherein the auxiliary discharge is an alternating current discharge performed through a dielectric. (4) The gas laser device according to claim 1, wherein the high impedance has at least a resistance component.