JPS5932185A - Silent discharge type gas laser device - Google Patents

Abstract

PURPOSE:To readily control a discharging power by forming a metal layer which deform an electric field on the part which generates a silent discharge of a discharge tube. CONSTITUTION:Metal layers 21, 22 are formed as trigger electrodes on the inner surface of a discharge tube 1 in the vicinity of electrodes 2, 3. The metal layers 21, 22 are formed in a discharge space, thereby producing a distortion in an electric field in the discharge space. Accordingly, as the high frequency voltage applied between the electrodes 2 and 3, a discharge occurs from the periphery of the layers 21, 22. Thus, a discharge starting voltage of this axial flow type laser device becomes a low voltage value, and the relationship between the applied voltage and the discharge power becomes a smooth curve. In this manner, the control of the discharge power can be readily performed. Even when the metal layer is arranged on the outer surface of the discharge tube, similar effects can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silent discharge type gas laser device (hereinafter referred to as an axial flow type laser device) in which the axial direction of the discharge tube and the optical axis direction coincide with each other, and in particular, the discharge can be easily started. The present invention relates to an axial flow laser device that can achieve 51C.

Conventionally, this type of axial flow laser 1 device is shown in Figure 1 (a).
) There was something that showed K. In this figure, 1 is a discharge tube made of a dielectric material such as glass, 2.3 is an electrode (blood) provided in close contact with the outer peripheral surface of the discharge tube 1, and 4 is an electrode 2.3. For example, I O+l KH7, ] (IKV voltage is connected to both electrodes 2
．． It is applied for 3 hours. Reference numeral 5 denotes a discharge space within the spreader 1 sandwiched between the electrodes 2 and 3. 6 is a total reflection mirror, I is a partial reflection mirror, and this total reflection @ 69 partial reflection mirror T is arranged at both ends KN of the discharge space 50 to form an optical resonator.

8 is a laser beam output from the partial reflecting mirror T. Arrow 9 indicates the direction in which the laser gas flows, and as shown in FIG. 1, it circulates in the axial flow laser device.

10.11 is the air pipe.

12 is a heat exchanger for lowering the temperature of the laser gas whose temperature has risen above tK in the discharge space 5, and 13 is a blower for circulating the laser gas.

Figure 1(b) shows the discharge tubes 1 and 1N7 in the discharge space 5 of Figure 1(a)! It is a figure which shows the cross section of L pole 2.3.

The above is the configuration of the conventional axial flow type laser device, and the operation thereof will be explained next.

First of all, a pair of 1! A multi-frequency high navigation pressure is applied to the L poles 2 and 3 from a high frequency power source 4, and a stable glow-like discharge known as a silent discharge is generated in the tortoise space 5. discharge space 5
The laser gas passing through is excited by the discharge energy of this silent discharge, and the excited laser gas enters a resonant state in the optical resonator formed by the total reflection mirror 6 and the partial reflection mirror 7, and is emitted from the partial reflection mirror 1. A laser beam 8 is output.

This laser beam 8 is used for purposes such as laser processing.

As above -tfl@2. When a laser beam 8 is obtained by applying a high frequency voltage between the electrodes 2 and 3, the emission force changes as shown in FIG. 2 with respect to the change in the voltage applied between the electrodes 2 and 3. It is clear from Figure 2 that the electric field inside the 5VC discharge tube 1 is close to uniformity, so the voltage applied between the electrodes 2 and 3 is a fairly large voltage value ■.

When this happens, discharge will start. Furthermore, since the applied voltage near the voltage V at the start of discharge includes the discharge start process in every cycle, the emitted X power is equal to a in FIG. 2.

As shown in b and c, there was a problem in that variations occurred and it became difficult to control the emitted tx force.

This invention has been made in view of the above-mentioned points, and by providing a metal layer for electric field concentration near the electrode, the discharge starting voltage of an axial flow laser device can be lowered, and the discharge force can be easily controlled. It is an object of the present invention to provide an axial flow type laser device that eliminates the conventional drawbacks. The present invention will be explained below based on the drawings.

FIG. 3 is a sectional view of the discharge space 5 portion of the discharge space 5 of the axial flow type laser device showing an embodiment of the present invention. In FIG. 3, parts given the same reference numerals as those in FIG. 1 indicate the same parts, and therefore, description thereof will be omitted (the same applies to other drawings hereinafter). 21.22 is the It pole 2
, 3 is a metal layer that serves as a trigger electrode provided on the inner surface of the discharge tube 1σ).

For example, it is made of thermally sprayed aluminum. The thickness of this metal layer must be made as thin as possible without interfering with the optical path of the laser beam.

In this embodiment, the operation for obtaining the laser output is similar to that of the conventional device, but the change in discharge power with respect to the increase in voltage applied to the electrode 2.3 is as shown in FIG.

That is, the metal layer 2.1.22 which becomes the trigger 'IjL pole
By providing this in the discharge space 5, distortion will occur in the electric field within the discharge space 5.

Therefore, as the voltage applied between the electrodes 2.3 increases, discharge first occurs around the metal layers 21.22. Therefore, the discharge starting voltage in the axial flow laser device of this example is
As shown in FIG. 4, the positive α value vs' is as low as 5. The relationship between the applied voltage and the discharge power also becomes smooth as shown by the fourth curve. Therefore, the discharge power can be easily controlled even in an axial flow laser device that includes a periodic discharge start process every cycle.

Further, in the above embodiment, aluminum was thermally sprayed as the metal layers 21 and 22, but any metal layer that is thin enough not to interfere with the laser beam optical path will produce the same effects as in the above embodiment. Further, there is no need for it to be in close contact with the inner surface of the discharge tube 1. For example, a similar effect can be obtained by inserting a spring-like metal 23 shown in FIG.

In addition, in terms of distorting the electric field inside the discharge tube 1 and slowing down the discharge initiation process, the above embodiment also applies when metal layers 21 and 22 are provided on the outer surface of the discharge tube 1 at 5K as shown in FIG. Same as σ).

As explained above, the silent discharge gas laser device according to the present invention is provided with a metal layer on the inner or outer surface of the emitter tube that distorts the electric field in the discharge space in the portion of the emitter tube where silent discharge occurs. Since the discharge is initiated from the periphery of the metal layer, it would be extremely effective if the discharge starting voltage could be lowered and the discharge force could be easily controlled.

[Brief explanation of the drawing]

Figure 1 (8) is a diagram of the configuration principle of a conventional axial flow laser device.
Figure 1 (b) is a cross-sectional view of the discharge tube and electrode in the discharge space part of Figure 1 (a), and Figure 2 is the applied voltage and discharge power between the 11L poles of the conventional 11-flow type laser device. FIG. 3 is a cross-sectional view of the discharge tube, electrodes, etc. in the discharge space of an axial-flow laser device showing an embodiment of this invention, and FIG.
The figure shows the relationship between the voltage applied between the electrodes and the discharge power.
FIGS. 5 and 6 are cross-sectional views of a discharge tube, electrodes, etc. showing other embodiments of the respective inventions. In the figure, 1 is a discharge tube, 2.3 is an electrode, 4 is a high frequency power supply, 2
1.22 is a metal layer, and 23 is a spring-like metal. Note 1
The same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno - (1 other person) Figure 1 (a) Figure 4 ■Sv Applied voltage peak value Figure 5 Figure 6

Claims (1)

[Scope of Claims] (11) A pair of electrodes are disposed so as to face each other on the outer peripheral surface of a discharge tube made of dielectric material, and a high frequency high voltage is applied between these two IIL poles. In a silent discharge gas laser device that generates a silent discharge inside a discharge tube and uses this discharge as a laser excitation source to emit a laser beam in the axial direction of the discharge tube, an electric field is distorted in a portion of the discharge tube where the silent discharge occurs. A silent discharge type gas laser device characterized in that a metal layer is provided. (2) Claim No. to)
11+( of claim 11+(
Voice-release type gas nuza device.