JPS5849651Y2 - Carbon dioxide laser device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a carbon dioxide laser device, and particularly to a carbon dioxide laser device that can be operated for a long time without exchanging the laser medium gas.

Figure 1 is a cross-sectional view of a horizontally pumped high-speed circulation type carbon dioxide laser device taken up as a typical example of this type of carbon dioxide laser device. 3 is a discharge part, 4 is a wire mesh, 5 is a rod-shaped cathode,
6 is a heat-light exchanger, 6 is an axial blower, and 7 is a flow path connecting the heat exchanger 5 and the axial blower 6, which is a space for making the heat exchanger 5 work effectively.

8 is an airtight container that airtightly isolates these components from the outside air.

The axial blower 6 circulates the laser medium gas at high speed.

The laser medium gas blown out from the axial blower grows on the end wall surface of the airtight container 8, turns around, flows along the inner wall surface, turns around again on the other end wall surface, passes through the wire mesh 4, and flows into the discharge section 3. do.

The flow path is narrowed from the wire mesh 4 to the discharge section 3 and expanded again toward the heat exchanger 5. The reason for this is that the flow velocity in the discharge section 3 is set high and the flow velocity in other parts is set low. Then wire mesh 4
This is to reduce pressure loss in the heat exchanger 5.

The laser optical axis is located approximately at the center of the discharge section 3 in a direction perpendicular to the plane of the paper.

The wire mesh 4 uniformizes the flow velocity distribution in the optical axis direction, keeps the discharge stable, removes coarse dust, and cleans the laser medium gas.

The laser medium gas is, for example, 100 to 760 Torr CO
2, N2. While a mixed gas such as He is sealed in an airtight container 8 and circulated, a glow discharge is generated between an anode 1 and two rows of cathodes, and a laser beam is extracted in a direction perpendicular to the plane of the paper.

However, as described above, this device has a drawback in that the laser output gradually decreases over time as the time elapses after the gas sealing off operation is performed without constantly replacing the laser medium gas.

Figure 2 shows the change in laser output over time.
It can be seen that the laser output, which was W, decreased to about 0.27 kW (about 30% of the initial value) after about 150 hours.

According to research by the inventors, the main cause of this decrease in laser output over time is thought to be water vapor contained in the laser medium gas.

This is supported by the fact that by sealing an appropriate absorbent (e.g. zeolite, silica gel, etc.) in the airtight container 8 and dehumidifying the laser medium gas, it was possible to eliminate the decrease in laser output over time. .

Figure 3 is a characteristic diagram showing the dependence of laser output on the elapsed time after sealing off when a moisture absorbent is installed in an airtight container. It can be seen that the laser output remains constant even after a long period of time.

The main operating conditions of this device are that the pressure of the laser medium gas is 200 Torr, the discharge input is 7 KW, and the semi-mirror transmittance is 20%.

However, since the amount of moisture absorbed by the moisture absorbent is limited, it is necessary to appropriately renew or regenerate the moisture absorbent installed in the airtight container.

This invention aims to minimize the number of times the moisture absorbent is renewed and to minimize the amount of moisture that adheres to the inside of the airtight container during renewal, thereby increasing the operating rate of the laser device.

Figure 4 is a sectional view of an embodiment of this invention, where 9 is a moisture absorbent;
Reference numeral 10 denotes a container for containing the moisture absorbent 9, which is made of, for example, copper or aluminum having high thermal conductivity.

11 is a heater for heating and regenerating the moisture absorbent 9;
Examples include nichrome wire and commercially available baking tape heaters.

Reference numeral 12 denotes a cartridge that accommodates the moisture absorbent 9, the container 10, and the heater 11, and has a structure such that it can be easily attached and detached from a small opening 13 provided in a part of the airtight container 8.

14 is a sealing material. In the apparatus configured in this manner, the moisture absorbent 9 is regenerated by energizing the heater 11 when the sealing operation is finished and the laser medium gas is evacuated from the airtight container 8 using a vacuum evacuation device (not shown). Heating the moisture absorbent 9,
This is done by releasing moisture from the moisture absorbent 9.

Furthermore, the moisture absorbent 9 can be quickly replaced by opening the opening 13.

In addition to simplicity, the small opening 13 is advantageous for the following reasons.

That is, when the wall of the airtight container 8 is opened wide, a large amount of outside air enters, water vapor in the atmosphere adheres to the wall of the airtight container 8 and the components inside the device, and the amount of moisture absorbed by the adsorbent 9 increases, causing regeneration or renewal. This is because the period becomes shorter, which in turn leads to a decrease in the operating rate of the device, whereas if it is done quickly with a small opening 13, the amount of outside air that enters will be reduced, and the above-mentioned inconvenience can be alleviated.

FIG. 5 is a sectional view of another embodiment of this invention, where 15 is a stand and 16 is an infrared lamp.

In this way, the container 10 containing the moisture absorbent 9 may be replaced.

Further, instead of the infrared lamp 16, a heater may be provided on the pedestal 15.

This idea consists of a small opening configured to be airtightly sealed provided in an airtight container through which laser medium gas circulates, and a moisture absorbent disposed in the airtight container removably placed through this small opening. The carbon dioxide laser device is equipped with a container containing a hygroscopic material and a heating device that heats the moisture absorbent in the container, and can maintain high laser output over a long period of time, resulting in a carbon dioxide laser device with high operating efficiency.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional view of a conventional lateral excitation high-speed circulation type carbon dioxide laser device, Fig. 2 is a characteristic diagram showing the change in conventional laser output over time, and Fig. 3 shows the circulation path of the hygroscopic agent and the laser medium gas. FIG. 4 is a sectional view of one embodiment of this invention, and FIG. 5 is a sectional view of another embodiment of this invention. In the figure, 1 is an anode, 2 is a rod-shaped cathode, 3 is a discharge part, and 5
is a heat exchanger, 6 is an axial blower, 8 is an airtight container, 9 is a moisture absorbent, 10 is a container, 11 is a heater, 12 is a cartridge,
13 is a small opening, 15 is a pedestal, and 16 is an infrared lamp. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A device configured to generate a laser beam by circulating a laser medium containing CO2 gas in an airtight container to form a glow discharge, which is provided on the wall surface of the airtight container. a small opening configured to be airtightly sealed for taking in and out the moisture absorbent; and a heating device provided in the airtight container to heat and dehumidify the moisture absorbent installed in the airtight container. (2) A carbon dioxide laser device as set forth in claim 1 of the utility model registration claim, characterized in that the heating device and the container containing the moisture absorbent are configured into an integrated cartridge. Carbon dioxide laser device.