JPH0610712Y2 - TEA type laser device - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to TEA (Transversely Excited Atmospheric p
ressure) type laser device, and more particularly to a TEA type laser device having a laser mirror pair directly at both ends of a discharge chamber.

2. Description of the Related Art Conventionally, in a TEA type laser device, an insulating resin such as glass epoxy or acrylic is used for a discharge chamber, and EMI (electromagnetic inductio) is used.
n) Metal chambers are also widely used as laser discharge tubes for reasons such as countermeasures and durability. The shape of this metal chamber includes a cylindrical shape and a rectangular parallelepiped shape.

In the discharge chamber, whichever the shape of the cylinder or rectangular parallelepiped is, the upper part is heated by the heat generated by the discharge electrode inside the discharge chamber and the circulation fan for circulating the laser gas. .

For example, if one circulation fan is a 25 W axial flow fan and five such axial flow fans are used, a total of 125
A heat quantity of W is generated. Even if most of the heat is taken away by using an appropriate heat exchanger installed inside the discharge chamber, this heat amount will differ in the temperature of the atmosphere outside the discharge chamber, and the axial fan or discharge electrode that is the heat source Due to the arrangement, even in a metal chamber having a high heat transfer efficiency, a temperature difference of about several degrees occurs between the upper part and the lower part.

Even if a cross flow fan that installs the motor drive unit outside the discharge chamber is used instead of the axial flow fan without using the axial flow fan that is the largest heat source in the discharge chamber, the external motor drive unit The heat generated by the heat remains in the upper part of the housing covering the discharge chamber.

Normally, a circulation fan is installed to prevent heat from being trapped inside the case, but unless you have a fairly large-scale air conditioning system, the upper and lower parts inside the case are inevitably several degrees Celsius.
The above temperature difference occurs. At this time, since the metal chamber has a good thermal conductivity, it absorbs the heat inside the housing, and again, a temperature difference occurs between the upper part and the lower part of the metal chamber. Therefore, there is a drawback that the stability of the optical resonator is significantly reduced due to this temperature difference.

In the case of a TEACo ₂ laser having a total reflection mirror having a curvature of R = 15 m and an output mirror having a curvature of R = ∞, in the case of a TEACo ₂ laser having an optical resonator length of about 1 m, the discharge direction of the main discharge is perpendicular to the mirror gimbal. It was confirmed that the mirror gimbal rotates about ± 20 μrad in that direction, and the beam pattern in that direction is reduced by about 10%. It can be seen that the number of 20 μred is a number caused by a temperature difference of about 1 ° C. when aluminum having a linear expansion coefficient of 23.2 × 10 ⁻⁶ deg ⁻¹ is used for the metal chamber.

As described above, in the case of the TEACo ₂ laser, strict optical resonator stability is required, and thus, until now, both ends of the metal chamber have not been used as optical resonators, and an invar rod or the like is provided outside the metal chamber. The optical resonator spacing is fixed with a material having a small expansion coefficient to maintain the stability of the optical resonator.

However, this complicates the structure of the laser oscillator, and since there is a rod around the metal chamber for fixing the optical resonator spacing, it may be an obstacle when replacing maintenance parts in the laser chamber. Not a few, it was difficult to maintain the laser oscillator.

The purpose of the present invention The present invention has been made to eliminate the above-mentioned drawbacks of the conventional one, and enhances the stability of the optical resonator and
It is an object of the present invention to provide a TEA type laser device that can be easily maintained.

The TEA type laser device according to the present invention forms a part of a pulse shaping circuit in a TEA type laser, and has a rectangular parallelepiped metal discharge chamber, and a discharge chamber provided in the discharge chamber and having a laser cavity. A cooling water flow path, which is provided at four corners of the rectangular parallelepiped along the axial direction and circulates the cooling water maintained at a constant temperature, and the discharge chamber facing each other.
A pair of laser mirrors that are installed on the surfaces of the pair and that form a laser resonator.

Embodiment Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. First
Figure (a) is a front view of one embodiment of the present invention, (b) is (a)
Is a left side view of (a), (d) is a plan view of (a), and (e) is a bottom view of (a).

In these figures, mirror gimbals 2 and 3 forming an optical resonator are attached to a metal discharge chamber 1, and a discharge port 1 of a main discharge electrode (not shown) is attached to the discharge chamber 1. A laser gas circulation fan (not shown) and an outlet 5 of a heat exchanger (not shown), a cathode 6 of the main discharge electrode, an insulating plate 7 for insulating the cathode 6, and a window for visually observing the main discharge of the main discharge electrode. And 8 are provided. Further, at four corners in the discharge chamber 1, cooling passages 9-1 to 9-4 (cooling passages 9-3, 9) for circulating temperature-controlled cooling water or cooling oil are circulated.
-4 is not shown).

Here, the window 8 and the outlet 5 have the same size, and the outlet 4 and the insulating plate 7 have the same size. Also, the cooling path 9-1
When circulating cooling water to ~ 9-4, resistance is 1MΩ / cm
Use the above pure water.

As the material of the discharge chamber 1, a material having good thermal conductivity such as aluminum, stainless steel, or iron is selected, and the discharge chamber 1 itself is cooled by cooling an appropriate place to control the temperature inside the discharge chamber 1. Even if is used as an optical resonator, its stability is constant regardless of the repetition rate, the discharge input power, and the temperature of the atmosphere outside the discharge chamber.

Insulation plate 7 for insulating the discharge port 4 of the main discharge electrode and the cathode 6 provided on the respective surfaces of the discharge chamber 1 facing each other.
And the discharge chamber 1 so that the outlet 5 of the laser gas circulation fan and the heat exchanger and the window 8 for viewing the main discharge of the main discharge electrode have the same size. By designing, the twisting of the discharge chamber 1 can be minimized even with a slight temperature change.

The cooling water circulating in each corner of the discharge chamber 1 is ±
The temperature is controlled below 1 ° C.

The optical resonator length is about 1m, the height of the discharge chamber 1 is 0.25m,
With the width of 0.4 m, the stability of the mirror gimbals 2 and 3 can be suppressed to ± 5 μrad or less.

If the stability can be suppressed to this extent, almost no change in the pattern of the laser light is recognized, and the laser oscillator can withstand a light source such as a laser marker.

FIG. 2 is a block diagram showing the configuration of another embodiment of the present invention. In the figure, the discharge chamber 1 has a laser mirror 1
Fixing flange 1 for fixing the mirror gimbals 2, 3 between the mirror gimbals 2, 3 for attaching 0, 11
2 and 13 are directly welded. Also, the discharge chamber 1
Cooling paths 9-1 to 9-4 are provided therein as in the embodiment of the present invention.

In another embodiment of the present invention, the parallelism of the fixed flanges 12 and 13 directly welded to the surface of the discharge chamber 1 on the contact surfaces of the mirror gimbals 2 and 3 is about 1/10 (see "/" in the figure). /0.1A-A ”) enables easy alignment when the mirror gimbals 2 and 3 are attached to the discharge chamber 1 during assembly or maintenance.

That is, by setting the gap between the fixed flanges 12 and 13 and the mirror gimbals 2 and 3 to be a constant distance with a thickness gauge or the like, it is possible to easily bring the state close to the best alignment. No laser or jig such as He-Ne for alignment is required, unlike the conventional method.

FIG. 3 is a configuration diagram showing a configuration of a pulse shaping circuit utilizing one embodiment of the present invention and a part of another embodiment. In the figure, the discharge chamber 1 includes a housing 17 and insulators 15, 16
Is installed through. Further, a pulse shaping circuit utilizing one embodiment of the present invention and a part of another embodiment is composed of a storage capacitor 18, a start switch 19, a discharge resistor 20, an HV power supply 21, and a cathode terminal 22. ing.

Since a metal is used for the discharge chamber 1, the discharge chamber 1 is used in a pulse shaping circuit for discharging between the main discharge electrodes.
It is possible to use a part of. That is,
The metal having good thermal conductivity used in the discharge chamber 1 has a physically small specific resistance, and the discharge chamber 1 has a sufficiently large surface area suitable for passing a high frequency current. Is fully usable as a part of.

When a pulse shaping circuit is assembled directly from the anode of the main discharge electrode with a wide copper plate, etc., other circuit components that make up the pulse shaping circuit are surrounded by this copper plate, making maintenance difficult. It was troublesome. This is because the pulse shaping circuit can be constructed by using the copper plate 23 having a narrower width than the conventional one by configuring the pulse shaping circuit by using one embodiment of the present invention and part of the other embodiments. It can be realized directly from the anode of the discharge electrode without forming a pulse shaping circuit with a wide copper plate or the like. Therefore, the main discharge electrode, which is a consumable component, can be replaced without removing the copper plate 23, and the maintenance of the discharge chamber 1 becomes very easy.

Further, since the connection between the cathode 6 of the main discharge electrode of the discharge chamber 1 and the cathode terminal 22 is made by using a spring, the replacement of the main discharge electrode is easy by removing the flange surface of the anode 14 of the main discharge electrode. Can be done.

A cooling medium having a high degree of insulation, such as pure water or cooling oil, is used to cool the interior of the discharge chamber 1 so that the pulse shaping circuit can be closed by one circuit. If the discharge chamber 1 is attached to the housing 17 without interposing the insulators 15 and 16 and a liquid having a low degree of insulation is used as a cooling medium, a high frequency current will flow to the ground of the housing 17 and the inside of the oscillator or this ground will flow. It may cause malfunction or damage to other control devices connected to.

In this way, cooling paths 9-1 to 9-4 for circulating a cooling liquid such as pure water or cooling oil are provided at four corners in the metal discharge chamber 1 having a rectangular parallelepiped in parallel with the optical axis of the laser beam. By providing the optical resonator, the stability of the optical resonator can be improved and the maintenance can be easily performed.

Although the discharge chamber 1 is made of metal in one embodiment and another embodiment of the present invention, a resin discharge chamber is also provided with a cooling passage for circulating a cooling liquid such as pure water or cooling oil therein. Therefore, it is obvious that the stability of the optical resonator can be increased, and the present invention is not limited to this.

As described above, according to the present invention, by circulating the cooling liquid in the discharge chamber, the stability of the optical resonator can be enhanced and the maintenance can be easily performed. There is.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention, FIG. 2 is a configuration diagram showing a configuration of another embodiment of the present invention, and FIG. 3 is a diagram showing one embodiment and another embodiment of the present invention. It is a block diagram which shows the structure of the pulse shaping circuit which uses a part. Explanation of symbols of main parts 1 ... Discharge chamber 4 ... Main discharge electrode outlet 5 ... Laser gas circulation fan and heat exchanger outlet 7 ... Insulating plate 8 ... Main discharge electrode main discharge is visually inspected Windows for cooling 9-1 to 9-4 ... Cooling path, 22 ... Cathode terminal 12, 13 ... Fixed flange 15, 16 ... Insulator, 23 ... Copper plate

Claims (1)

[Scope of utility model registration request] 1. A discharge chamber made of a metal in the shape of a rectangular parallelepiped and forming a part of a pulse shaping circuit in a TEA type laser, and the rectangular parallelepiped provided in the discharge chamber and along the optical axis direction of the laser resonator. A cooling water flow path that circulates cooling water that is maintained at a constant temperature and that is provided at four corners of
A TEA type laser device comprising: a pair of laser mirrors that are installed on a pair of opposing surfaces of the discharge chamber and that constitute a laser resonator.