JP3044060B2 - Laser gas supply control device in gas laser oscillator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a laser gas supply control device in a gas laser oscillator.

(Prior art) A gas laser oscillator using a gas such as CO ₂ gas as a laser medium generally excites a laser gas, which is a laser medium, by discharge from a discharge electrode between an anode electrode and a cathode electrode in an oscillator chamber. Has become.

The oscillator chamber of the gas laser oscillator is evacuated by a vacuum pump, and a laser gas is supplied from a laser gas supply source such as a gas cylinder. The supply amount of the laser gas to the oscillator chamber is constant in order to obtain a constant chamber internal pressure in order to stabilize the laser output in a steady state.

As a method of controlling the internal pressure of the oscillator chamber, the laser gas flow rate is controlled by a fixed metering diaphragm member provided in the middle of the laser gas supply passage from the laser gas supply source to the oscillator chamber, and the exhaust passage by the vacuum pump is opened and closed by an on-off valve. There are known a method of selectively performing exhaust, and a method of controlling a flow rate of exhaust gas by providing a fixed metering throttle member in the exhaust gas passage instead of the laser gas supply passage.

(Problems to be Solved by the Invention) When the gas laser oscillator is started up for a long time or after a long stoppage, the stability of the laser output is low due to impurities, moisture, dust, etc. attached to the inside of the oscillator chamber. There is a problem that the time required for the laser output to reach a steady state at which the laser output reaches the rated output from the time of starting, that is, the time required for startup is longer than that at the start.

As a countermeasure for this, a special long-time discharge or a gas exchange in the oscillator chamber is performed several times.

However, the measures described above do not significantly reduce the time required for startup, and may increase operating costs.

The present invention has been made in view of the above-described problems in the conventional gas laser oscillator, and has been described in view of the above-described problems. It is an object of the present invention to provide a laser gas supply control method in a gas laser oscillator which can sufficiently reduce the time.

(Means for Solving the Problems) The present invention has been made in view of the above-mentioned conventional problems, and has been described in view of the fact that an oscillator chamber and a gas supply source in a gas laser oscillator are provided with a first gas flow allowing a large flow of laser gas.
And a second passage permitting the flow of the laser gas at a small flow rate are provided in parallel with each other via a parallel passage provided in parallel, and at a branch portion between the first passage and the second passage, An electromagnetic switching valve that functions to close the second passage when the gas supply source is connected to the first passage and to close the first passage when the gas supply source is connected to the second passage, And calculating a temporal gradient of the laser output detected by the laser output sensor. When the temporal gradient is greater than a predetermined threshold value, the first passage is opened and the second passage is closed. An arithmetic and control unit for controlling switching of the electromagnetic switching valve so as to close the passage and open the second passage is provided.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a reference example of a laser gas supply control device.

In FIG. 1, reference numeral 1 denotes an oscillator chamber of a gas laser oscillator. The oscillator chamber 1 is provided with a discharge electrode (not shown) for exciting a laser gas in a general structure. .

In the oscillator chamber 1, carbon dioxide gas is supplied from a gas cylinder 3.
A laser gas composed of a mixed gas such as a nitrogen gas and a helium gas is supplied through a laser gas supply passage 5.

The laser gas supply passage 5 has two parallel passages 7 and 9 connected in parallel with each other on the way. Parallel passages 7, 9
Are provided with metering throttle members (orifices) 11 and 13, respectively. Weighing flow metering diaphragm member 11 and 13 are different from each other, in this case, in the flow rate Q ₁ into the metering throttle member 11 is larger than in the flow rate Q ₂ to the metering diaphragm member 13. The flow rate Q ₁ is a large flow rate required at the time of start-up required at the time of steady-state, the flow rate Q ₂ is a small flow rate required at the time of steady state.

An electromagnetic switching valve 15 is provided at a branch portion between the parallel passages 7 and 9. The electromagnetic switching valve 15 closes the parallel passage 9 and opens the parallel passage 7 when the power is supplied, and the parallel passage 7 when the power is not supplied.
Is closed and the parallel passage 9 is opened.

The energization of the electromagnetic switching valve 15 may be performed by a timer control device for a predetermined time, for example, about 10 to 20 minutes from the start of the start of the gas laser oscillator.

Thereby, the parallel passage 9 is closed for a predetermined time from the start of the start of the gas laser oscillator, and the parallel passage 7 is closed.
It opens, metering throttle member 11 the laser gas generator chamber 1 at a large flow rate Q ₁ required at the time of launch laser gas through the
After a predetermined time has passed since the start of startup,
That is, the steady state closed parallel passage 7 opens parallel passage 9, the laser gas through the metering diaphragm member 13 comes to the laser gas at a low flow rate Q ₂ required for steady state flows into the oscillator chamber 1.

After the gas laser oscillator allowed to stand for 2 days, and supplies only 15 minutes from the time of start-up commence at twice the large flow rate to Q ₁ small flow rate Q ₂ of the laser gas to the oscillator Chanbai, then the laser gas flow to a small flow rate Q ₂ and when reduced, as a small flow rate Q ₂ of the laser gas flow from the first, the experimental results of the change in the in the laser output in the case did not alter this is shown in Figure 2. In this case, T ₁ is 15 minutes, T ₂ becomes 3 hours, it was performed a significant amount of start-up time reduction.

FIG. 3 shows an embodiment of the laser gas supply control device according to the present invention. In FIG. 3, portions corresponding to FIG. 1 are indicated by the same reference numerals as those given in FIG.

In this embodiment, the laser output detected by the laser output sensor 17 incorporated in the gas laser oscillator is
Input to the arithmetic and control unit 19 including the AI function and the like, the arithmetic and control unit 19 calculates the temporal gradient of the laser output from the change of the laser output every predetermined time, and when this is larger than the predetermined threshold value, the electromagnetic switching valve The power is supplied to the electromagnetic switching valve 15 when the time-dependent inclination is smaller than a predetermined threshold.

Thus, when the temporal gradient of the laser output is larger than a predetermined threshold value, for example, at the time of startup, the parallel passage 9 is closed and the parallel passage 7 is opened, and the laser gas passes through the metering throttle member 11 and the large flow rate Q _1. When the laser output is smaller than a predetermined threshold value, such as in a steady state, when the laser output is stabilized, that is, when the laser output is stabilized, the parallel passage 7 is closed and the parallel passage 9 is closed. Opens,
Laser gas through the metering diaphragm member 13 is the laser gas to flow into the oscillator chamber 1 at a low flow rate Q _2.

FIG. 4 shows an example in which the laser output detected by the laser output sensor 17 is captured at each of the time points A, B, C, D,. .

In the above-described embodiment, the control of the supply amount of the laser gas supplied from the laser gas supply source to the oscillator chamber is performed by the flow rate control. However, the control may be performed by the pressure control. The control is not limited to two steps, and this may be a multi-step more or a quantitative continuous variable control. Further, the control of the supply amount of the laser gas is not limited to the start-up time, and may be performed at the time of steady state to save the laser gas.

In the above, the present invention has been described in detail with reference to specific embodiments. However, the present invention is not limited to these embodiments, and various embodiments can be made within the scope of the present invention. It will be clear to those skilled in the art.

[Effects of the Invention] As can be understood from the above description of the embodiments, in short, the present invention provides a method of controlling the flow of a laser gas at a large flow rate between an oscillator chamber (1) and a gas supply source (3) in a gas laser oscillator. The first passage (7) allowing the flow of the laser gas at a small flow rate and the second passage (9) allowing the flow of the laser gas at a small flow rate are provided in parallel with each other via a parallel passage provided in parallel with the first passage (7). When the gas supply source (3) and the first passage (7) are connected to a branch portion between the gas supply source (3) and the second passage (9), the second passage (9) is closed and the gas supply source is closed. (3) When the second passage (9) is connected, an electromagnetic switching valve (15) functioning to close the first passage (7) is provided, and the laser output detected by the laser output sensor (17) is provided. Is calculated, and this temporal gradient is larger than a predetermined threshold. The first passage (7) is opened and the second passage (9) is closed, and the electromagnetic valve (7) is closed so as to close the first passage (7) and open the second passage (9) when small. This is a configuration provided with an arithmetic and control unit (19) for controlling the switching of 15).

According to the present invention, according to the present invention, it is possible to determine whether or not the laser output is stabilized based on the time-dependent inclination of the laser output. When the laser output is stabilized, the laser gas is switched to a small flow rate. And the suppression of the consumption of the laser gas can be effectively performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a reference example of a laser gas supply control device, and FIG. 2 is a graph showing changes in the laser output when the flow rate of the laser gas supplied to the oscillator chamber is changed and when it is not changed. FIG. 3 is a schematic configuration diagram showing an embodiment of a laser gas supply control device according to the present invention, and FIG. 4 is a diagram showing a state in which a laser output detected by a laser output sensor at each time of a predetermined time is captured. 9 is a graph showing an example of calculating a temporal gradient of an output. DESCRIPTION OF SYMBOLS 1 ... Gas laser oscillator, 3 ... Gas cylinder 5 ... Laser gas supply passage, 7, 9 ... Parallel passage 11,13 ... Measurement throttle member, 15 ... Electromagnetic switching valve 17 ... Laser output sensor, 19 ... Arithmetic control unit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01S 3/097 H01S 3/03 H01S 3/104

Claims (1)

(57) [Claims] An oscillator chamber (1) and a gas supply source (3) in a gas laser oscillator have a first passage (7) allowing a large flow of laser gas and a small flow of a laser gas. A second passage (9) is connected in parallel via a parallel passage provided in parallel, and the gas supply is provided at a branch between the first passage (7) and the second passage (9). When the source (3) and the first passage (7) are connected, the second
An electromagnetic switching valve (15) that functions to close the first passage (7) when the gas supply source (3) is connected to the second passage (9), and A temporal gradient of the laser output detected by the laser output sensor (17) is calculated, and when the temporal gradient is greater than a predetermined threshold, the first passage (7) is opened to open the second passage (9). ) Is provided with an arithmetic and control unit (19) for controlling the switching of the electromagnetic switching valve (15) so as to close the first passage (7) and open the second passage (9) when it is small. Gas supply control device in a gas laser oscillator.