JPH0747885Y2 - TEA-CO2 laser oscillator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a TEA-CO ₂ laser oscillator used for marking, for example.

[Conventional technology]

TEA (Transverersery Excited Atomspheric, abbreviated below)
The —CO ₂ laser is a laser that oscillates by exciting discharge of CO ₂ gas laterally with respect to the oscillation direction of the laser.
This TEA-CO ₂ laser is a laser that oscillates infrared rays in the vicinity of 10 μm, and because it is difficult to maintain the discharge state, pulse oscillation is unavoidable, but conversely, it has a large peak power and can operate at atmospheric pressure. It has features. Conventionally, it has been used for processing such as marking of electronic parts and isotope separation.

FIG. 2 is a schematic explanatory view of such a conventional TEA-CO ₂ laser oscillation device. FIG. 2A is a cross-sectional view in a direction perpendicular to the oscillation direction, and FIG. ) Is a cross-sectional view taken along the line YY in the oscillation direction, and FIG. 3 is a diagram for explaining the oscillation operation of the TEA-CO ₂ laser oscillator. Reference numeral 11 is an anode forming a main electrode, 12 is a cathode forming a main electrode, 21 is an anode forming a pair of auxiliary electrodes for preionization, 22 is a cathode forming a pair of auxiliary electrodes for preionization, 3 Is a fan for sending the laser gas to the discharge space 4, 5 is a high reflection mirror, 6 is an emission mirror, 10 is an outer wall of the chamber, 7 is a high voltage charger, 8 is a main condenser, and 9 is a spark gap switch.

As shown in FIG. 2, the TEA-CO ₂ laser oscillator is designed as a resonator in order to increase the distance that the light guide passes through the laser medium to cause more stimulated emission required for laser oscillation. The high-reflecting mirror 5 and the emitting mirror 6 are configured to form a long discharge space 4 in the optical axis direction. Therefore,
The main electrodes 11 and 12 for discharge-exciting the laser gas from the direction of oscillation of the laser, that is, the direction orthogonal to the optical axis direction, are plate-shaped ones that are long in the optical axis direction. Is arranged so that the discharge space 4 is elongated in the horizontal direction. That is, the laser oscillation direction is horizontal.

Also, an auxiliary electrode used for preionization of laser gas
A plurality of 21, 22 are evenly arranged along the side edges of the main electrodes 11, 12 as shown in FIG. 2 so that ultraviolet rays are uniformly transferred to the discharge space.

2 and 3, when the main capacitor is charged by the high voltage charger 7 and the spark gap switch 9 is turned on by the trigger signal, the peaking capacitor 21 is charged and discharged while the auxiliary electrodes 21 and 22 for preionization are charged. Arc discharge. The ultraviolet rays generated by the arc discharge uniformly ionize the laser gas in the discharge space 4. In this state, electrification reaches the main electrode, high voltage is applied between the anode 11 and the cathode 12, and glow discharge is started. The laser gas that has been ionized and ionized in advance emits light when excited by this glow discharge, is induction-amplified by the high reflection mirror 5 and the emission mirror 6 that form a resonator, and is oscillated by the emission mirror 6. The laser gas is generally CO ₂ : N ₂ : C.
A mixture of O: He and a partial pressure ratio of 8: 8: 2: 82 is used.

In order to remove the laser gas heated by the discharge and replace it with fresh laser gas, a fan 3 having a radiator R behind it is provided at a position facing the discharge space 4, and the main electrode
Laser gas is sent in a direction perpendicular to the direction of discharge by 11,12.

A thyratron may be used instead of the spark gap switch 9.

[Technical issues to be solved by the device]

As described above, the TEA-CO ₂ laser oscillating device is used for processing such as marking, but when it is incorporated in a processing device, it is necessary to downsize the device and save space.
Here, the conventional TEA-CO ₂ laser oscillator, because as long discharge space in the horizontal direction is formed, the elongated main electrodes are arranged toward the longitudinal direction in the horizontal direction, TEA-CO ₂ The bottom area occupied by the laser oscillator is inevitably large.

In this case, by arranging the main electrodes so that the longitudinal direction thereof is oriented in the vertical direction so that a long discharge space is formed in the vertical direction, a TEA-CO ₂ laser oscillator with a small occupied area becomes possible.

However, lengthening the discharge space in the vertical direction means
This means that the laser is oscillated in the vertical direction, and the high reflection mirror and the emission mirror are inevitably arranged above and below the discharge space. In this case, there arises a problem that dust adheres to the high reflection mirror or the emission mirror arranged below the discharge space. That is, there is a problem that foreign matter generated by discharge such as electrode sputtering becomes dust and drops and adheres to the high reflection mirror or the emission mirror. If rubber adheres to the mirror, the laser absorbs heat and is not reflected, resulting in a decrease in laser output or a defect in the output laser irradiation pattern. As a result, in the case of marking, for example, this leads to defects in the marked pattern.

[Purpose of device]

This invention was made in consideration of the above problems,
A TEA-CO ₂ laser oscillator that occupies a small area is created by forming a long discharge space in the vertical direction, and at that time, dust falls on the high-reflection mirror or emission mirror located below the discharge space. Prevents adhesion and reduces the laser output and eliminates defects in the output laser irradiation pattern.
The purpose is to provide a TEA-CO ₂ laser oscillator.

〔Constitution〕

In order to achieve such an object, the TEA-CO ₂ laser oscillator of the present invention includes a pair of vertically long plate-shaped main electrodes arranged facing each other facing a discharge space and extending in the vertical direction of the main electrodes. A pair of auxiliary electrodes for preionization arranged along the side edge, and a chamber outer wall accommodating the main electrode and the auxiliary electrode,
A fan that is housed inside the chamber outer wall and circulates a laser gas in a space between the main electrode and the bottom of the chamber outer wall from a direction substantially perpendicular to the discharge direction and a fan that circulates the laser gas, and is disposed vertically above and below the discharge space. A high reflection mirror and an emission mirror, wherein the high reflection mirror or the emission mirror is arranged below a laser passage hole provided at the bottom of the chamber outer wall, and extends toward the chamber side surrounding the laser passage hole.
A dust fall prevention member having a knife edge at its tip is provided.

[Action]

According to the TEA-CO ₂ laser oscillating device having the above-mentioned configuration, since a discharge space long in the vertical direction is formed, the area occupied by the device can be reduced, and dust on the high reflection mirror or the emission mirror arranged below the discharge space can be reduced. There is no drop adhesion and no decrease in laser output or defects in the laser irradiation pattern that is output.

〔Example〕

 Embodiments of the present invention will be described below.

FIG. 1 is a schematic explanatory view of a TEA-CO ₂ laser oscillating device according to an embodiment of the present invention. FIG. 1A is a cross-sectional view in the horizontal direction, and FIG. It is sectional drawing in the vertical direction in -X. 30 is a fan, 40 is a discharge space, 100 is an outer wall of the chamber, 101 is a bottom of the outer wall of the chamber, 102 is a laser transparent passage hole, 103 is a dust fall prevention member, 51 is a bellows, 52 is a gas hose, 53 is a joint, 54 is a holder. Reference numeral 5 denotes a high reflection mirror, and the same reference numerals in FIG. 2 denote the same or corresponding portions.

As is clear from FIG. 1 (b), TEA-CO _{2 of} this example.
In the laser oscillating device, the pair of main electrodes 11 and 12 are arranged in the vertical direction in the longitudinal direction, and the high-reflecting mirror 5 and the emitting mirror 6 are arranged above and below the discharge space 40 which is long in the vertical direction, and the laser is vertically arranged. It is configured to oscillate in the direction. As a result, the area occupied by the bottom portion 101 of the chamber outer wall can be reduced, and as a result, the area occupied by the entire apparatus can be reduced.

In FIG. 1B, a hole 102 for laser transmission is provided in the bottom portion 101 of the outer wall of the chamber so that the resonance of the laser by the high reflection mirror 5 and the emission mirror 6 provided below is not hindered. . The fan 30 includes a pair of main electrodes 11 and 12.
Parallel to the anode 11 side and in the space between the anode 11 and the bottom portion 101 of the chamber outer wall, a pair of main electrodes 11, 12 and the bottom portion 1 of the chamber outer wall from the direction substantially perpendicular to the direction of discharge.
The laser gas is circulated and supplied to the space between 01 and the discharge space 40. As is well known, since the gas in the discharge space 40 flows in a direction substantially perpendicular to the discharge direction, it is possible to achieve higher laser pulse repetition than in the case where the gas flows in a direction parallel to the discharge direction. .

Foreign matter such as sputtering generated by the discharge of the main electrodes 11 and 12 and the auxiliary electrodes 21 and 22 falls due to gravity,
Especially the bottom hole of the fan 30 for the laser passage hole
Since the dust is carried by the gas flow formed on the upper part of the 102, it does not fall from the laser transmission hole 102 and adhere to the high reflection mirror 6. Further, the conveyed foreign matter collides with the side surface of the chamber outer wall (the surface parallel to the electrode), and as a result, becomes dust and collects on the bottom portion 101 of the chamber outer wall. The dust collected on the bottom portion 101 of the chamber outer wall moves so as to crawl on the bottom portion 101 of the chamber outer wall due to the gas flow by the fan 30. However, in this embodiment, as shown in FIG. 1C, since the dust drop prevention member 103 surrounding the laser transmission hole 102 and extending toward the chamber is provided, the dust is prevented from falling from the laser transmission hole 102. Therefore, it does not adhere to the high reflection mirror 6. The height h of the dust drop prevention member 103 may be about 10 mm, depending on the flow rate of the laser gas. still,
Since the end portion 104 is formed into a knife edge shape, the following results are further obtained. That is, the knife-edge-shaped end portion 104 can move the dust that has moved along the bottom portion 101 of the outer wall of the chamber so as to move away from the laser transmission hole 102 again. Further, the flow of the gas flow formed above the laser transmission hole 102 is less likely to be disturbed. If the tip of the dust drop prevention member 103 is cylindrical, a vortex is generated at the end. Therefore, the dust also enters the dust fall prevention member 103 and falls and adheres to the high reflection mirror 6 arranged below the discharge space.

In addition, the TEA-CO ₂ laser oscillator of the present embodiment has an adjusting means (not shown) for adjusting the distance between the high reflection mirror 5 and the emission mirror 6 to an optimum resonance distance for the oscillation wavelength. It is provided. The bellows 51 is for enabling the resonance distance to be adjusted by the adjusting means.

In the above embodiment, the high-reflection mirror 5 is arranged below the discharge space 40 and the emission mirror 6 is arranged above.
It is also technically equivalent to dispose the high-reflecting mirror 5 on the lower side and the high-reflecting mirror 5 on the upper side only by reversing the direction of oscillation.

Further, operation of the laser oscillation of the conventional shown in FIG. 3 TEA-CO ₂
Since it is the same as the case of the laser oscillator, the description thereof is omitted.

[Effect of device]

As described above, the TEA-CO ₂ laser oscillator of the present invention comprises a pair of vertically long plate-shaped main electrodes arranged facing each other facing the discharge space and the side edges of the main electrodes in the vertical direction. A pair of auxiliary electrodes for pre-ionization arranged along the line,
A chamber outer wall accommodating the main electrode and the auxiliary electrode, and a laser gas is circulated and supplied to the space between the main electrode and the chamber outer wall bottom and the discharge space from a direction housed inside the chamber outer wall and substantially perpendicular to the discharge direction. Since it is composed of a fan and a high reflection mirror and an emission mirror which are arranged above and below with the discharge space interposed therebetween, a discharge space long in the vertical direction is formed,
The area occupied by the device can be reduced. Therefore, when it is incorporated in a processing device for marking or the like, it is suitable because it meets the demand for space saving. Further, the high reflection mirror or the emission mirror is arranged below the laser passage hole provided at the bottom of the outer wall of the chamber, a gas flow is formed above the laser passage hole by the fan, and the laser passage hole is surrounded. Since it is equipped with a dust drop prevention member that extends to the chamber side and has a knife edge-shaped tip, dust is placed below the discharge space by a gas flow that does not create a vortex. The dust that has been removed from the chamber and moved to crawl on the bottom of the outer wall of the chamber moves again away from the laser transmission hole, and there is no drop of dust on the high-reflecting mirror or the emission mirror. There is no defect in the irradiation pattern of the output laser. Therefore, for example, when it is used for marking, it does not cause defects in the pattern to be marked, which is preferable.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a TEA-CO ₂ laser oscillating device according to an embodiment of the present invention. FIG. 1 (a) is a cross-sectional view in the horizontal direction, and FIG. 1 (b) is X- of FIG. 2 is a vertical sectional view taken along line X, FIG. 2 is a schematic explanatory view of a conventional TEA-CO ₂ laser oscillator, and FIG. 2 (a) is a sectional view taken in a direction perpendicular to the oscillation direction. (B) is a cross-sectional view taken along the line YY in the same figure as (a), and FIG. 3 is a diagram for explaining the oscillation operation of the TEA-CO ₂ laser oscillator. In the figure, 11 …… Anode forming the main electrode 12 …… Cathode forming the main electrode 21 …… Anode forming the auxiliary electrode 22 …… Cathode forming the auxiliary electrode 3,30 …… Fan 4,40 …… Discharge space 5 ... High-reflection mirror 6 ... Emitting mirror 10,100 ... Chamber outer wall 101 ... Chamber outer wall bottom 102 ... Laser transmission hole 103 ... Dust drop prevention member.

Claims (1)

[Scope of utility model registration request] 1. A pair of vertically long plate-shaped main electrodes arranged facing each other facing a discharge space, and a plurality of preionization electrodes arranged along a vertical side edge of the main electrodes. The auxiliary electrode, the chamber outer wall accommodating the main electrode and the auxiliary electrode, and the space between the main electrode and the chamber outer wall bottom from the direction substantially perpendicular to the direction of discharge housed inside the chamber outer wall and the discharge space. It is equipped with a fan that circulates a laser gas, and a high-reflection mirror and an emission mirror that are arranged above and below with a discharge space in between, and the high-reflection mirror or the emission mirror is below the laser passage hole provided on the bottom of the outer wall of the chamber. A TEA-CO ₂ laser oscillating device, characterized in that it is provided with a dust drop prevention member that is disposed in a space surrounding the laser passage hole, extends toward the chamber, and has a knife edge-shaped tip.