JPH0352279A - Gas laser oscillator - Google Patents

Abstract

PURPOSE:To detect extinction of discharge surely by judging extinction of discharge if the output from a photosensor for detecting light generated through discharge drops below a set value, and outputting an alarm signal. CONSTITUTION:Light 6 is generated through discharge, a photodiode 7 is irradiated therewith, and the photodiode 7 outputs current corresponding to the amount of received light. The current is converted by a converter 8 into a voltage signal D1, which is then input to a comparator 10. The comparator 10 compares the value of the signal D1 with a set value Dr stored in a memory 9, and generates an alarm signal Sa if it is the value Dr or less. Thus, extinction of discharge can be surely detected without influence of the irregularity of the characteristics, of a discharge tube 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas laser oscillator that excites a laser gas in a discharge tube by an electric discharge to generate laser oscillation, and particularly relates to a gas laser oscillator that can detect extinction of the electric discharge.

[Conventional technology]

Generally, in a discharge-excited gas laser oscillator, a discharge current is detected, fed back to a power source for laser gas excitation, and compared with a command value to perform current control and control laser output.

On the other hand, in this type of laser oscillator, the discharge may disappear during the base discharge due to an abnormal increase in gas pressure inside the discharge tube. When the discharge disappears, the terminal voltage of the excitation power supply increases due to the increase in impedance between the electrodes of the discharge tube. However, if you accidentally receive a laser output command and try to increase the discharge current while the discharge is extinguished, the excitation The output voltage of the power supply may further rise abnormally and the internal semiconductor components may be destroyed.

For this reason, for example, an alarm signal is generated by detecting a voltage increase when the discharge disappears, and subsequent laser output commands are not accepted.

[Problem to be solved by the invention]

However, in reality, the voltage at the time of extinction of the discharge shows different values due to variations in the discharge tube, etc., so the threshold must be changed accordingly, making the adjustment complicated and causing problems with the accuracy of the alarm. was there.

The present invention has been made in view of these points, and an object of the present invention is to provide a gas laser oscillator with improved detection accuracy of discharge extinction.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention provides a gas laser oscillator that excites laser gas in a discharge tube by electric discharge to generate laser oscillation, which is installed near the discharge tube and receives light generated along with the electric discharge. an optical sensor that outputs a signal according to the amount of received light; and a comparison circuit that compares the signal from the optical sensor with a set value and outputs a predetermined alarm signal indicating extinction of the discharge when the signal falls below the set value. Provided is a gas laser oscillator characterized by having the following.

[Effect]

During discharge, light is generated along with the discharge, so this is detected by the optical sensor, and when the output of the optical sensor drops below a set value, it is assumed that the discharge has disappeared and an alarm signal is output. The state of discharge extinction can be reliably detected without being affected by variations in discharge tube characteristics.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the hardware configuration of a high frequency discharge excited laser oscillator according to an embodiment of the present invention. In the figure, an excitation power source 1 rectifies alternating current power from a commercial power source (not shown) and then switches it to generate a high frequency voltage of, for example, 2 MHz.

When this high frequency voltage is applied to the electrodes 2a and 2b provided on the surface of the discharge tube 2, a discharge is generated inside the discharge tube 2, and laser gas (not shown) circulating at high speed inside the discharge tube 2 is excited. laser beam is generated.

Note that the value of the discharge current is measured by the current measuring circuit 3, and the measured value is manually input to the calculator 4.

The calculator 4 calculates the difference between the set value from the output setting circuit 5 and the measured value from the current measuring circuit 3, and instructs the excitation power source 1 to output according to this difference.

Therefore, the discharge current is controlled to be approximately equal to the set value, and a laser output is generated according to this current value.

On the other hand, light 6 is generated along with the discharge and is irradiated onto the photodiode 7. The photodiode 7 then outputs a current according to the amount of received light, which is converted by the conversion circuit 8 into a voltage signal D1 and input to the comparison circuit 10. Comparison circuit 10
converts the value of the signal D1 to the setting value Dr stored in the memory 9.
compared to the set value Dr, the alarm signal S
generate a. The control circuit 1l stops the operation of the excitation power source 1 when the alarm signal Sa is input.

In the above explanation, the operation of the excitation power source 1 is stopped by the alarm signal Sa, but at the same time, for example, an alarm indicating extinction of the discharge may be displayed on the display device.

〔Effect of the invention〕

As explained above, in the present invention, the light generated due to the discharge is detected by the optical sensor, and when the output of the optical sensor decreases below a set value, it is assumed that the discharge has disappeared and an alarm signal is output. The discharge extinction state can be detected reliably. Further, this set value does not need to be changed in accordance with the voltage, current characteristics, etc. of the discharge tube, and adjustment is easy. Furthermore, since the operation of the excitation power source is stopped immediately upon detection of extinction of the discharge, even if a laser output command is issued by mistake at this time, the excitation power source will not be destroyed, improving reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a laser oscillator according to an embodiment of the present invention. 1 2 6 7 10 D] Dr Sa Excitation power supply Discharge tube light photodiode comparison circuit Signal setting value/Alarm signal

Claims (3)

[Claims] (1) In a gas laser oscillator that excites laser gas in a discharge tube with an electric discharge to generate laser oscillation, the gas laser oscillator is installed near the discharge tube, receives the light generated by the discharge, and outputs a signal according to the amount of light received. A comparison circuit that compares the signal from the optical sensor with a set value and outputs a predetermined alarm signal indicating extinction of the discharge when the signal from the optical sensor decreases below the set value. gas laser oscillator. (2) The gas laser oscillator according to claim 1, characterized in that the operation of the excitation power source is stopped by the alarm signal. (3) The gas laser oscillator according to claim 1, wherein the optical sensor is comprised of a photo diode.