JPH0376283A - Gas laser device - Google Patents

Abstract

PURPOSE:To dispense with an expensive vacuum tube of high capacity and to prevent a vacuum tube from decreasing in service life by a method wherein the output of a high frequency power source section is limited to a range that it is larger than a level where the plate loss of the vacuum tube becomes maximal and smaller than a rated level. CONSTITUTION:An output setting device 16 of a control circuit 15 sets the output P of a high frequency power source 1 so as to range from an output level Pa larger than a level where a plate loss PL becomes equal to a maximum value PLa to a level smaller than a rated output level Pb. Therefore, the control circuit 15 sequentially controls the high frequency power source 1 so as to set its output P to a set point within the range of the output level Pa to Pb. That is, when a gas laser is made to start operating, the high frequency power source 1 usually increases the output P starting from a zero level toward the rated level Pb but it is kept out of operation through the control circuit 15 until it is put in a state that is can output the output level Pa, and a control power is fed to the power source 1 to start when it is put in a state that it is able to output the output level Pa.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a gas laser device excited by high-frequency discharge using a high-frequency power source using a vacuum tube.

(Prior art) For example, an axial flow type gas laser device excites the laser gas at high frequency by supplying power output from a high frequency power supply section to electrodes that sandwich a discharge tube in which laser gas is circulated through an impedance matching device. This is a configuration for extracting laser light.

Conventionally, it has been common to use a vacuum tube amplification type as the high frequency power supply section in this type of gas laser device. In other words, in a solid-state amplified high frequency power supply section,
This is because the turn-on and turn-off times of solid-state devices are too long to obtain high frequencies, especially frequencies of 10 MHz or higher, and the current capacity is small.

(Problem to be solved by the invention) In a gas laser device using a vacuum tube amplified high-frequency power supply section, an impedance matching box is designed so that matching is achieved near the rated output and maximum laser light output is obtained. Therefore, in the low output range of the power supply, the reflected waves increase and the plate loss of the vacuum tube reaches its maximum value.

Vacuum tubes are generally used with plate losses below the allowable value, because if the plate loss becomes excessive, the tube will become overheated and its life will be shortened, and if it becomes significantly excessive, it will break. Therefore, it is necessary to use a vacuum tube for the high-frequency power supply section with a plate loss tolerance greater than the above-mentioned maximum value, but this requires the use of an expensive vacuum tube with a large capacity. In addition, even if a vacuum tube with a plate loss tolerance higher than the above-mentioned maximum value is used, if there is not enough room for the difference, the maximum plate loss will change due to temperature changes, aging, etc. until the maximum plate loss exceeds the tolerance. This often happens, resulting in a problem that shortens the life of the vacuum tube.

The present invention has been made in view of the above circumstances, and its purpose is to provide a gas laser device that does not require the use of large-capacity and expensive vacuum tubes in the high-frequency power supply section, and that can prevent shortening of the life of the vacuum tubes. It is on offer.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a gas laser device in which a laser beam is extracted by applying a power output from a high-frequency power supply section using a vacuum tube to a discharge section to excite a laser gas. The present invention is characterized in that a control means is provided for limiting the power output of the high-frequency power supply unit to a range greater than a level indicating a maximum plate loss of the vacuum tube and within a rated level.

(Function) According to the gas laser device of the present invention, the power output of the high frequency power supply section is limited by the control means to be greater than the level indicating the maximum plate loss of the vacuum tube. Therefore, a vacuum tube with a small capacity can be used.

(Example) An example of the present invention will be described below with reference to the drawings.

First, the overall configuration will be described according to FIG.

Reference numeral 1 denotes a vacuum tube amplification type high frequency power supply unit having a vacuum tube 2 . That is, 3 is an exciter, and its high frequency power is applied to the grid of the vacuum tube 2 via a driver amplifier 4 which is a pre-stage amplifier. Further, the high frequency output, which is the plate output of the vacuum tube 2, is outputted to an output terminal 9 via a filter 8 consisting of an axle 5 and a capacitor 6.7. Reference numeral 10 denotes a discharge section of an axial gas laser device, which includes a discharge tube 11 through which laser gas is circulated, and electrodes 12 and 13 disposed to sandwich the discharge tube 11. electrode 12.13
In between, the high frequency power output from the output terminal 9 of the high frequency power supply unit 1 is supplied via an impedance matching device 14.

A control circuit 15 is a control means, and is equipped with an output setting device 16. The control circuit 15 sequentially controls the high frequency power supply section 1 so that its high frequency power output is limited to a range of output levels set in advance in the output setting device 16 and described later.

Next, the operation of this embodiment will be explained with reference to FIG. 2 as well.

First, when a control power source is applied to the high frequency power supply unit 1 under the control of the control circuit 15, the exciter 3 generates high frequency power, and the high frequency power is first amplified by the driver amplifier 4 and then sent to the vacuum tube 2. The signal is applied to the grid, where it is further amplified and output as a high frequency power output P from the output terminal 9. The high frequency power output P is then supplied to the discharge section 10 via the impedance matching device 14. As a result, the laser gas in the discharge tube 11 is excited by high-frequency discharge and generates light, which is repeatedly reflected by reflection mirrors (not shown) disposed at both ends of the discharge tube 11 and then extracted as a laser beam. It is something. In this case, the impedance matching device 14 adjusts the laser light output LO of the discharge section 10 to the maximum value LO at the rated output pb of the power supply output P of the high frequency power supply section 1.
Since the vacuum tube 2 is matched so as to output a, the reflected wave increases in the low output region of the power supply output P, and the plate loss PL of the vacuum tube 2 reaches a maximum value PLa.

Therefore, in this embodiment, the output setter 16 of the control circuit 15 sets the power output P of the high frequency power supply section 1 to within the rated output level Pb from an output level Pa that is greater than the level at which the maximum value PLa of the plate loss PL occurs. Therefore, the control circuit 15 controls the high frequency power supply unit 1 so that its power output P falls within the range of output level Pa to pb.
Sequence control is performed to maintain the set range of .

That is, for example, when a gas laser device is operated, the high frequency power supply section 1 normally increases the power supply output P from the 0 level toward the rated level pb.
In this embodiment, the control circuit 15 makes it inactive (control power is not supplied) until the power output P reaches the state where it outputs the output level Pa.
Control power is supplied and the device operates when it is ready to output. Further, when processing a workpiece with a gas laser device, the power output P is adjusted to adjust the laser light output LO depending on the material of the workpiece, processing conditions, etc. Even in this case, in this embodiment, When the power supply output P is adjusted to be less than the output level Pa, the control circuit 15 stops the high frequency power supply section 1.

Generally, in the vicinity where the power output P of the high frequency power supply section 1 reaches the output level at which the plate loss PL of the vacuum tube 2 exhibits the maximum value PLa, almost no laser light output LO is output. The output level P
There is no problem even if it is set to a value higher than a.

According to this embodiment, the following effects are achieved. That is, since the power output P of the high-frequency power supply unit 1 is limited to a level greater than the output level Pa at which the vacuum tube 2 exhibits the maximum value PLa of the plate loss PL, the vacuum tube 2 can be operated at a level where the allowable plate loss value is greater than or equal to the maximum value PLa. There is an advantage that there is no need to use a large-capacity, high-priced one, and a small-capacity, low-priced one can be used.

Furthermore, even if the allowable plate loss value of the vacuum tube 2 approaches the maximum value PLa, the power output P will not decrease until it reaches the maximum value PLa of the plate loss PL, as described above, so temperature changes, aging, etc. Even if there are changes,
The life of the vacuum tube 2 is not shortened.

Although the above embodiment is a case where the present invention is applied to an axial flow type gas laser device, the present invention is not limited to this, and can be similarly applied to a two-axis orthogonal or three-axis orthogonal cross-flow type gas laser device. [Effects of the Invention] As explained above, the gas laser device of the present invention is equipped with a control means for limiting the power output of the high frequency power supply section using a vacuum tube to a set range, so that the high frequency power supply section does not have a large capacity and is expensive. This eliminates the need to use vacuum tubes, and has the excellent effect of preventing shortening of the life of the vacuum tubes.

[Brief explanation of drawings]

FIG. 1 is an electrical configuration diagram showing an embodiment of the present invention, and FIG. 2 is a characteristic diagram for explaining the operation of the embodiment. In the drawing, 1 is a high frequency power supply section, 2 is a vacuum tube, 10 is a discharge section, 11 is a discharge tube, 12 and 13 are electrodes, 14 is an impedance matching device, 15 is a control circuit (control means), and 16 is an output setting device. show. 6 Figure 1

Claims (1)

[Claims] 1. In a gas laser device that extracts laser light by applying a power output from a high frequency power supply section using a vacuum tube to a discharge section to excite laser gas, the power output of the high frequency power supply section is determined by the plate loss of the vacuum tube. 1. A gas laser device characterized in that a control means is provided for limiting the range to a range greater than a level indicating a local maximum value and within a rated level.