JPH0240975A - Gas laser oscillator - Google Patents

Abstract

PURPOSE:To obtain laser oscillation of high quality by vapor depositing carbon on the inner wall surface of a discharge tube. CONSTITUTION:Carbon 14 of about several mum thick is vapor-deposited on the inner wall of a cylindrical discharge tube 1. By the effect of the carbon deposition film 14, the reflectivity of the inner wall of the discharge tube 1 is extremely decreased, and standing wave is scarcely reflected. As a result, the generation of noisy light is remarkably restrained, so that the noisy light is scarecely mixed in the laser beam emitted from a partial reflection mirror, and very high quality light is obtained. Thereby, e.g., in the case of cutting working, the finish precision of a worked surface is improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gas laser oscillation device in which the axial direction of a discharge tube and the optical axis direction coincide with each other, and particularly relates to a gas laser oscillation device that can oscillate a high-quality laser beam. It is related to the device.

[Conventional technology]

Conventionally, as this type of gas laser oscillation device, for example, the third
As shown in Fig. 4 and Fig. 4, a pair of metal electrodes (2) (3) are arranged at a predetermined interval on two places on both sides of the outer peripheral surface of a cylindrical discharge tube (1) made of a dielectric material such as glass. ) are disposed in close contact with the opposing canes, and the pair of metal electrodes (2) and (3) are connected to a high frequency AC power source (4),
For example, 13.511iMHz, 2
While applying a high frequency high voltage of kv, both metal electrodes (2)
(3) A total reflection mirror (6) and a partial reflection mirror (7) are arranged at fixed positions at both ends of the discharge space (5) in the discharge tube (1) sandwiched between these mirrors. (6) and partially reflective mirror (
7) constitutes an optical resonator, and an air pipe (8) is connected from the center between the electrodes (2) and (3) of the discharge tube (1).
A pair of branch pipes (9) and (10) are provided in communication with both pipes (1) and (8) between both ends of the discharge tube (1) and the other end of the air supply pipe (8). Arrange the discharge tube ('I)
A pair of circulation passages branching in two directions from the center of the
In history, a blower (11) is provided in the middle of the air pipe (8), and air pipes (8) are provided on both sides of the blower (11).
a discharge in the discharge space (5) and a blower (11);
A heat exchanger (
12) A so-called axial flow type gas laser oscillation device is known, which is provided with (13).

Note that the blower (11) needs to have a blowing capacity capable of producing a gas flow at a flow rate of about 100 m/see in the discharge space (5).

In the conventional device with the above configuration, first, a pair of metal electrodes (2)
When a high-frequency high voltage is applied to (3) from the high-frequency power source (4) to generate a glow-like discharge in the discharge space (5), the laser gas passing through the discharge space (5) obtains the discharge energy and is excited. At the same time, the optical resonator formed by the total reflection mirror (6) and the partial reflection mirror (7) enters a resonant state, whereby a laser beam (B) is output from the partial reflection mirror (7). This laser beam (B
) will be used for purposes such as laser beading.

By the way, in the conventional structure described above, the inner wall surface of the discharge tube (1) is made of, for example, a reflective glass.

[Problem to be solved by the invention]

However, in such a case where the inner wall surface of the discharge tube (+) is reflective, if there is a positional shift between the total reflection mirror (6) and the partial reflection mirror (7), the discharge tube (
The standing wave that is totally reflected by the inner wall surface of the laser beam (+) is amplified and a part of it is emitted as noise light through the partially reflecting mirror (7), so this noise mixes into the laser beam (B). There was a problem that it adversely affected laser processing.

The present invention was made to solve these conventional problems, and by eliminating reflections on the inner wall surface of the discharge tube, it is possible to oscillate a high-quality laser beam without mixed light. The first purpose is to provide equipment.

[Means to solve the problem]

In order to achieve the above object, the present invention causes a laser gas to flow in the optical axis direction in a discharge tube made of a dielectric material, and applies an island wave voltage between metal electrodes provided on the outer peripheral surface of the discharge tube. A gas laser oscillation device that generates a discharge in a discharge tube and uses the discharge as a laser excitation source to generate a laser beam in the axial direction of the discharge tube, characterized in that carbon is deposited on the inner wall surface of the discharge tube. be.

[For production]

With the above configuration, the present invention has an extremely low reflectance on the inner wall surface of the discharge tube due to vapor-deposited carbon even when the total reflection mirror and the partial reflection mirror are misaligned. Therefore, the generation of noise light is greatly suppressed, and the laser beam is hardly mixed with noise light, so that a high quality laser beam can be obtained.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

This embodiment device has the same basic configuration as the conventional example described above, so parts with the same configuration and function will be given the same reference numerals, and their explanation will be omitted to avoid duplication. do.

In FIG. 1, in the gas laser oscillation device according to this embodiment, carbon (I4) of several μ (microns) is deposited on the inner wall surface of a cylindrical discharge tube (1). This carbon deposited film (I4) extremely reduces the reflectance of the inner wall surface of the discharge tube (+), and standing waves are hardly reflected.
The generation of stray light is significantly reduced. Therefore, the laser beam (B) emitted from the partially reflecting mirror (7) is of high quality with almost no stray light mixed in, and can improve the finishing accuracy of the machined surface during cutting, for example. .

Fig. 2 shows the difference in the roughness of the cut surface between the conventional example and the present invention, and as is clear from this result, in the device of the present invention, there is a carbon vapor deposited film on the inner wall surface of the discharge tube (I). (I4
), the finishing accuracy of the cut surface is significantly improved.

〔Effect of the invention〕

As explained below, according to the present invention, carbon is deposited on the inner wall surface of the discharge tube to significantly lower the reflectance of the inner wall surface, so that a high-quality laser beam without any stray light can be produced. This has resulted in excellent effects such as improving the accuracy of laser machining such as cutting.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a discharge tube showing an embodiment of the present invention, Fig. 2 is a bar diagram showing the difference in roughness of cut surfaces between the conventional example and the present invention, and Fig. 3 is a conventional example. FIG. 4 is a longitudinal sectional front view of the example, and FIG. 4 is a longitudinal sectional side view of a conventional discharge tube. (1)...discharge tube, (2)(3)...metal electrode,
(+4)...Carbon. Gyakuhen'de chewing elephant 31 Mi (Norigo J No. 3 2 (3)

Claims (1)

[Claims] A laser gas is caused to flow in the optical axis direction within a discharge tube made of a dielectric material, and a high frequency voltage is applied between metal electrodes provided on the outer circumferential surface of the discharge tube to generate a discharge within the discharge tube, and this discharge is used as a laser excitation source. A gas laser oscillation device that generates a laser beam in the axial direction of the discharge tube, characterized in that carbon is deposited on an inner wall surface of the discharge tube.