JPS6356973A - Laser exciting device - Google Patents

Abstract

PURPOSE:To obtain a laser output of a high crest value caused by a short-time discharge by fixing the capacitors for storing the charges required for a pair of opposedly placed discharge electrodes to cause a discharge between the discharge electrodes as spacers. CONSTITUTION:Four capacitors 16 are charged to about 15-20KV by a d.c. power supply 14, and this charging voltage is continuously applied across an anode 4 and a cathode 3. In this condition, when a pulse power supply 21 provides a gate pulse to a thyristor 20 to momentarily turn it on, the potential of a preliminary discharge electrode 12 rises to cause a spark discharge between a preliminary discharge electrode 11 and simultaneously to ionize with ultraviolet rays a mixed gas containing a CO2 gas in the primary discharge space wherein the anode 4 and the cathode 3 are opposed to each other. Also, an avalanche discharge phenomenon is induced by the ionization between both electrodes, causing a laser oscillation. In this case, since the four capacitors 16 are directly connected to the primary discharge electrodes, the connecting conductors between the two become the shortest thereby making the inductance of the discharge circuit remarkably small, which enables a short-time discharge as well as availability of a laser output of a short pulse, high crest value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser excitation device that excites a laser medium gas by generating a glow discharge.

[Prior Art] As this type of laser, excimer laser (Exci+
wer La5er) or Transversely Excited A
tmosphericpressureccJ2Las
er, hereinafter referred to as TEA CO2L/-za). Figure 3 shows a conventional TEA coz laser excitation device.
FIG. 3 is a partially cutaway perspective view. In the same figure, a partial reflection mirror (2) is attached to one end of a metal cylinder (1) forming a laser excitation space, and a total reflection mirror (not shown) is attached to the other end, and a cathode (3) is attached inside the metal cylinder (1). and an anode (4) are arranged facing each other with a predetermined gap to form a discharge section (5). In addition, there is a pre-@i't near the cathode (3).
A preliminary discharge electrode (6) for ta is provided, and a fan (7) for circulating gas below the anode (4) is also provided. On the other hand, the outside of the metal cylinder (1) is charged by a high voltage power source (8), and the charging voltage is applied between the cathode (3) and the anode (4), or , a capacitor (3) for applying voltage between the cathode (3) and the preliminary discharge electrode (6).

With this configuration, a mixed gas containing carbon dioxide at about 1 atm is supplied to the inside of the metal cylinder (1), while the charging voltage of the capacitor (9) is transferred between the cathode (3) and the anode (4), and between the cathode (3) and the anode (4). and the preliminary discharge electrode (6) respectively, a glow discharge occurs in the discharge part (5), the mixed gas is excited, and the laser beam (10) is emitted from the partially reflecting mirror (2).
is emitted.

[Problems to be Solved by the Invention] In the conventional laser excitation device configured as described above, the capacitor (9) is installed outside the metal cylinder (1) 7, and the capacitor (8) and the metal cylinder ( 1) Since each internal electrode was connected with a conductive wire, the stray inductance of the discharge circuit increased and instantaneous discharge was not possible, making it difficult to obtain a laser output with a high wave peak value.

In addition, a cathode (3) is housed inside the metal cylinder (1).
) and the anode (4), it is necessary to keep the mutual spacing constant, but there is a problem in that it is difficult to keep the spacing constant over a long period of time, and the discharge state also varies.

On the other hand, a capacitor (9) installed outside the metal cylinder (1)
) uses a variety of different shapes, but they occupy a considerable amount of space, making it difficult to downsize the entire device.

The present invention has been made to solve the above-mentioned problems, and aims to provide a laser excitation device that can stably extract laser output with a high peak value over a long period of time, and that can be easily miniaturized.

[Means for Solving the Problems] In the laser excitation device according to the present invention, a capacitor that stores the electric charge necessary for causing a discharge between a pair of facing discharge electrodes is fixed as a spacer between the discharge electrodes. .

[Function] In this invention, by using a capacitor as a spacer of the discharge electrode to obtain a discharge suitable for laser excitation,
The connecting conductor between the two can be kept as short as possible, and at the same time, the stray inductance of the discharge circuit can be minimized, and a laser output with a high peak value can be obtained by short-time discharge. Furthermore, by using a capacitor as a spacer for the discharge electrodes, the gap between the electrodes is maintained constant over a long period of time, resulting in a stable discharge state. Furthermore, if a capacitor is used as a spacer for the discharge electrode, the number of capacitors installed outside the metal cylinder can be significantly reduced, thereby making it possible to downsize the entire device.

[Example 1] Figures 1 and 2 show an example of this invention.
Of these, FIG. 2 is an electric circuit diagram of the TEA CO2 laser excitation device, and FIG. 1 is a bait-view diagram showing the detailed configuration of the main parts of this device. In each of these figures, the cathode (3) and anode (4), which are arranged opposite to each other with a predetermined gap, are made of a porous iron plate press-molded smoothly into the shape of a ship's bottom. Electrode pairs (11) and (12) are installed. Here, the preliminary discharge electrode (11) has a rectangular cross section and is formed elongated in the axial direction of the metal cylinder (1) shown in FIG.

The number of pre-discharge electrodes (12) are pin-shaped and are held such that their tips face the side surfaces of the pre-discharge electrodes (11). Further, at the base end of the preliminary discharge electrode (12), I
One end of a resistor (13) of about KΩ is connected, and the other ends are commonly connected. On the other hand, it is equipped with a DC power source (14) for causing a glow discharge between the anode and the electrode, and the positive electrode is connected to the anode (4) via a resistor (15) of approximately IONΩ.
The negative electrodes are each connected to a cathode (3). moreover,
Four 10 gF capacitors (16) are connected in parallel between the anode (0) and the cathode (3). Also, a DC power supply (17) is used to apply voltage between the preliminary discharge electrodes (11) and (12). ), the positive electrode of which is a preliminary discharge electrode (11
) and a cathode (3), and the negative electrode is connected to the mutual junction of the resistors (13) via a resistor (18) of about INΩ and a capacitor (19) of about lpF. Then, the cathode of a thyristor (20) whose 7 nodes are grounded is connected to the mutual junction of the resistor (18) and the capacitor (19) in order to start a preliminary discharge, and the pulse power source (21) is connected to the thyristor (10). ) is designed to give a gate pulse.

Note that the above-mentioned cathode (3), anode (4), and capacitor (1B) are integrally constructed as shown in FIG. That is, both the cathode (3) and the anode (4) have a plate thickness of 1.5 mm. Os+ is made of a rectangular porous iron plate with holes of 2 mm diameter drilled at a pitch of 2.6 mm and a porosity of 52%, with the central part of the plate width bent to resemble the bottom of a ship. The capacitor (16) is a cylindrical ceramic capacitor with a diameter of 60 m and a height of about 20 m. These capacitors [16] are each fixed as a spacer between the cathode (3) and anode (4) that are arranged opposite each other, and are integrated by tightening the corners of the electrode plates with screws (22). At the same time, they are also electrically connected. In addition, the cathode (3) and the anode (4)
For external connection, a cathode lead (31) and an anode lead (41) are led out from the sides of the electrode plate, respectively.

The operation of the laser excitation device configured as described above will be explained below.

First, the four capacitors (16) are charged to about 15 to 20 KV by the DC power supply (14), and this charging voltage is constantly applied between the anode (4) and the cathode (3).

In this state, when the pulse power source (21) applies a gate pulse to the cyrisk (20) to turn it on momentarily, the potential of the pre-discharge electrode (12) rises, and the potential between the pre-discharge electrode (11) and the A spark discharge is generated, and when this is emitted, ultraviolet rays ionize the mixed gas containing 002 gas in the main discharge space where the anode (4) and cathode (3) face each other. Further, by tapping '1', an avalanche discharge phenomenon is induced between both electrodes and laser oscillation occurs.

In this case, the four capacitors (1B) are directly connected to the main discharge electrode, so the connecting conductor between them becomes the shortest and the inductance of the discharge circuit becomes significantly smaller, which allows short-time discharge of less than IJL seconds. Along with becoming
Laser output with short pulses and high peak values can be obtained.

In addition, since spacers are inserted at each of the four corners between the anode (4) and cathode (3), the gap can be maintained constant over a long period of time, which helps stabilize discharge and laser oscillation. It will be done.

Furthermore, in conventional installations, the main discharge capacitor (16) was installed outside the metal cylinder (1), which limited the ability to miniaturize the entire device; however, in this embodiment, the main discharge capacitor (16) is housed inside the metal cylinder, making it easier to downsize the device.

In the above embodiment, the case where there are four main discharge capacitors (16) was explained, but it may be necessary to use more spacers depending on the shape, material, etc. of the anode 8i (4) and the cathode (3). In some cases, five or more capacitors with small capacitances may be fixed as spacers.

Furthermore, although the above embodiments have been described with respect to the case of a TEA co2 laser, it goes without saying that the present invention can also be applied to an excimer laser in which oscillation is performed by pulse discharge excitation using a high-pressure laser gas.

[Effects of the Invention] As is clear from the above explanation, according to the present invention, the capacitor that stores the discharge charge is fixed as a spacer between the discharge electrodes, so that the laser output with a high wave peak value can be stably maintained over a long period of time. It has the effect that it can be taken out easily and can be easily miniaturized.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of essential parts of an embodiment of the present invention, FIG. 2 is an electric circuit diagram of the same embodiment, and FIG. 3 is a perspective view of a conventional laser excitation device. In the figure, (3) is the cathode, (4) is the anode, (+2) and (13) are the preliminary discharge electrodes, (14) is the DC power supply, and (16) is the capacitor. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa Figure 2 3F Pt book! = (fJ'Xtt book can) 4:P4 camphor (
・ ) Figure 3

Claims (2)

[Claims] (1) A laser excitation device that arranges a pair of discharge electrodes facing each other in a laser excitation space that supplies laser medium gas, and applies a charging voltage of a capacitor between the discharge electrodes to cause glow discharge and excite the laser medium gas. A laser excitation device according to the invention, wherein the capacitor is arranged and fixed between the discharge electrodes as a spacer. (2) The capacitor is composed of four cylindrical capacitors connected in parallel, and each of the cylindrical capacitors is arranged at four corners of the discharge electrode. Laser excitation device.