JPS61125094A - Dc discharge type gas laser device - Google Patents

Abstract

PURPOSE:To make the entire device compact and to improve reliability, by connecting inductance to a ballast resistor in series, thereby suppressing the rapid increase in current, which is generated when glow discharge is transferred to arc discharge. CONSTITUTION:A cathode is used as a divided electrode 1. Its shape is a pin shape. As an inductance part 4, a ferrite core 6, around which conductor is wound, is used. As a result, a power source and a discharge part can be made compact and simple, and an inexpensive, highly reliable laser device can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a direct current discharge type gas laser device using a gas discharge such as 001.

[Technical background of the invention and its problems]

FIG. 2 is a schematic cross-sectional view of a conventional DC lateral discharge gas laser device. As shown in the figure, the cathode is divided into a plurality of pin-shaped electrode segments 1, each of which is fixed by an insulator 5. 2 is an anode electrode. 3 is a ballast resistor for stabilizing the discharge. In order to perform high-power laser oscillation in a small size, the discharge power density must be high.

A stable and spatially uniform glow discharge must be generated over the entire discharge area. Similarly, G indicates the gas flow direction. In order to generate such a discharge, a discharge stabilizing resistor 3 called a ballast resistor is connected in series between the electrode and the power source.

However, if the discharge current is increased by increasing the output power of the laser, instability will occur regardless of the presence of a ballast resistor, and a transition from glow discharge to arc discharge will occur. In order to suppress this discharge instability, many methods have been considered in the past, and a method using auxiliary discharge has been particularly effective. Other methods include providing an independent power supply for each divided electrode and controlling the current between the divided electrodes and the divided electrodes using a semiconductor element (for example, Japanese Patent Laid-Open No. 12889-1989
0° JP-A-55-128892) has been proposed.

However, the former method requires a separate auxiliary discharge power supply, and the latter method requires the use of a large amount of high-voltage semiconductor elements, and in both cases, the power supply is large, complicated, and expensive. There were some drawbacks, such as: Furthermore, in the former case, the electrical sign necessary for auxiliary discharge is added to the discharge section, which has the disadvantage of making the device larger and more complicated.

[Purpose of the invention]

This invention improves the drawbacks of the conventional device described above, and aims to provide a low-cost, highly reliable, high-output DC discharge type gas laser device in which the entire device is made into a shed.

[Summary of the invention]

In order to achieve small-sized, high-output laser oscillation, it is necessary to generate a stable glow discharge that is uniform and has a high discharge power density over the entire discharge area. By connecting an inductance in series to the ballast resistor, this DC discharge type gas laser device suppresses the sudden increase in current that occurs when transitioning from glow discharge to arc discharge, and suppresses discharge instability. Various causes of this instability are considered, including thermal instability and instability due to the production and disappearance of negative ions, but the growth time is approximately 100
It is n3ec~1m5ee. on the other hand.

By flowing the laser medium gas at high speed (50 to IQOm/s), the instability of the slow growth rate can be suppressed.

Currently, the problem of instability in high-power laser equipment is when the growth time is 100 μsec or less. In addition, the value of conventionally used ballast resistors is approximately 1
It ranges from 0 to 50 Ω.

Current rise time: 100nsec to 100asec
If the inheatance is set to 50Ω, the inductance range is 10mH to 1H. By using this inductance, there is no need to complicate the power supply section, and the discharge section can also be made smaller and simpler, resulting in an inexpensive and highly reliable device. Furthermore, it is possible to reduce the value of the ballast resistance, which will also help improve laser efficiency. By using a high resistance wire for the inductance winding, the ballast resistance and inductance can be integrated, and the device can be further downsized.

〔Effect of the invention〕

According to the present invention, both the power source and the discharge section can be made smaller and simpler, and the device can be made inexpensive and highly reliable. Furthermore, the efficiency of the laser is also improved.

[Embodiments of the invention]

An embodiment of this invention is shown in FIG. In this example, a divided electrode is used as a cathode, and the divided electrode has a bottle shape. In addition, ferrite core 6 is used as inductance 4.
Use a conductor wrapped around it. As a result, both the power source and the discharge section can be made smaller and simpler, making it possible to provide an inexpensive and highly reliable laser device.

[Other embodiments of the invention]

The split electrode may be used for the anode, or for both the cathode and the anode. When a split electrode is used for both an anode and a cathode, the present invention may be used for both electrodes or only for either one. Any structure and material may be used for the inductance as long as its value is within the range of 1 mH to 1H. Alternatively, it is also possible to further downsize the device by integrating the ballast resistor and inductance by using a high-resistance wire for the winding.

Furthermore, a diode (or a series circuit of resistor 7 and diode 8) may be connected in parallel to the inductance in order to prevent a reverse voltage generated in the inductance when the power is turned off. Alternatively, to avoid using a large number of diodes, the power supply may be provided with a slow off circuit 9 that turns on and off by gradually increasing or decreasing the voltage.

Even if the present invention is applied to a small laser that does not use split electrodes,
By reducing the ballast resistance.

It is effective because it improves laser efficiency.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of an embodiment of the present invention, and FIG. 2 is a schematic sectional view of a discharge section of a conventional laser device. i... Divided electrode, 2... Anode, 3... Ballast resistance, 4... Inductance, 5... Insulator for fixing the split electrode, 6... Power source for discharging. Agent: Patent Attorney Noriyuki Chika (and 1 other person) No. 1
figure

Claims (4)

[Claims] (1) In a direct current discharge type gas laser device, in which an anode and a cathode are disposed facing each other in a gas laser medium, and at least one of the electrodes is divided into a plurality of electrodes, the divided A direct current discharge type gas laser device characterized in that each electrode is connected in series with a ballast resistor and an inductance to a direct current power source for discharge. (2) The direct current discharge type gas laser device according to claim 1, wherein the winding constituting the inductance is a high resistance wire winding that integrates a ballast resistor and an inductance. (3) The DC discharge type gas laser device according to claim 1, characterized in that the inductance is 1 mH to 1H. (4) The DC discharge type gas laser device according to claim 1, characterized in that a diode is connected in parallel to the inductance.