JPH049391B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a gas laser oscillator.

Conventional Structure and Problems Gas laser discharge generally utilizes a glow discharge region, and its discharge characteristics exhibit negative resistance as shown by curve A in FIG. For this reason, a resistance element is connected in series with this discharge, and this resistance component is provided by a general resistor, vacuum tube, etc. The discharge starting voltage depends on the discharge length and gas pressure, but is generally 20 KV/m. Also, the discharge voltage is
The voltage is 10 KV/m at 50 mA, and a voltage of up to 10 KV is applied to the resistive element, so a high voltage withstand element is required. For this reason, two high-voltage power supplies are used to provide power supply characteristics as shown in the broken line B in Figure 1, but when there are many discharge sections, it is difficult to stably start all discharges. There are problems such as difficulty.

Purpose of the Invention The purpose of the present invention is to maintain a low voltage applied to a resistive element that adjusts discharge current, and to
An object of the present invention is to provide a gas laser oscillator that can stably start all discharges even when there are many discharge sections.

Structure of the Invention The gas laser oscillator of the present invention has an electrode arranged around the outer periphery of the discharge tube, a high frequency voltage can be applied to this electrode by a high frequency oscillator, and the voltage at both ends of the discharge tube is detected by a control circuit. The oscillation output of the high frequency oscillator is controlled so that the voltage at both tube ends of the discharge tube is a constant high voltage close to the power supply voltage. Through control, the voltage applied to the variable resistor connected in series with the discharge tube is maintained at a constant low voltage.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 2 to 4. In FIG. 2, 1 is a discharge tube. A high voltage DC power supply 2 and a resistance element 3 serving as a resistance component are connected in series to this. Here, a triode vacuum tube is used as the resistance element 3. The resistive element 5 is for detecting the discharge current, which is compared with a variable reference voltage, and the current comparison control circuit 4 changes the grid bias of the triode vacuum tube 3 to adjust the impedance of the triode vacuum tube 3 so as to maintain a constant current. is controlled. Reference numeral 6 denotes a power source whose voltage can be freely changed, and this power source 6, vacuum tube 3, resistance element 5, and current comparison control circuit 4 constitute a variable resistor. In this state, discharge tube 1 exhibits the discharge characteristics of curve A in Figure 1, so a voltage of 10 KV or more may be applied to the plate of triode vacuum tube 3, so a special vacuum tube with high withstand voltage is used. There is a need. Furthermore, the amount of heat generated in the triode vacuum tube 3 increases, resulting in increased power consumption.

Now, reference numeral 7 denotes an electrode made of a metal wire that is placed around the outer periphery of the discharge tube 1, and is connected to a high frequency oscillator 8 of a variable output voltage type. The resistive elements 9 and 10 are used to divide and detect the plate voltage of the triode vacuum tube 3, and send the plate voltage to the control circuit 11. The control circuit 11 controls the oscillation output of the high frequency oscillator 8 so as to reduce this plate voltage.

Figure 3 shows the output voltage of the high frequency oscillator 8 at 5KV,
Discharge tube 1 when set to 7KV and 10KV respectively
The discharge characteristics are 25KHz, respectively. As can be seen from the figure, by applying a high voltage in the low current region and lowering the voltage as the discharge current increases, the discharge characteristics can be kept almost constant. This voltage adjustment is performed by the control circuit 11. Curve C in FIG. 4 is an example of a discharge characteristic in which the voltage at both ends of discharge tube 1 is controlled to be substantially constant according to the above principle, and curve D is a power supply characteristic of DC power supply 2. In this way, the voltage at both ends of the discharge tube 1 (discharge characteristic curve C) is maintained at an almost constant high voltage close to the voltage of the DC power supply 2 (power supply characteristic curve D), so the variable resistor (three-pole A substantially constant low voltage (approximately 1 to 2 KV) is applied to the vacuum tube 3, resistance element 5, etc., and an element with a small withstand voltage can be used as the resistance element. Therefore, the reactive power consumed by the resistance component is reduced, and more than 80% of the power, which was less than 50% in the past, can now be used as discharge energy. In addition, since the high frequency current supplied to the electrode 7 only needs to be extremely small (0.1mA
(below), the high-frequency oscillator 8 can be of low capacity and can be easily attached to each discharge tube.
Even in a gas laser oscillator having a large number of discharge regions, each discharge can be controlled and the start of discharge can be stabilized.

Note that in the above embodiment, the high frequency oscillator 8
A variable output voltage type oscillator was used as the high frequency oscillator 8, and the output voltage was decreased/increased according to the increase/decrease in the discharge current. The output frequency may be decreased or increased, or both may be used.

Effects of the Invention According to the gas laser oscillator of the present invention, the voltage applied to the resistance element that adjusts the discharge current can be maintained at a low voltage, and even when there are many discharge sections, the entire discharge can be started stably. It will be done.

[Brief explanation of drawings]

Figure 1 is a diagram showing the discharge characteristics and power supply characteristics of a conventional example, Figure 2 is a configuration diagram of an embodiment of the present invention, and Figure 3 is a diagram showing the discharge characteristics and power supply characteristics of a conventional example.
FIG. 4 is a diagram showing discharge characteristics for explaining the effects of this embodiment, and FIG. 4 is a diagram showing discharge characteristics and power supply characteristics according to this embodiment. 1...discharge tube, 2...power supply, 3...triode vacuum tube (variable resistance), 4...current comparison control circuit (variable resistance), 5...
Resistance element (variable resistance), 6... Power supply (variable resistance), 7
...electrode, 8...high frequency oscillator, 11...control circuit.

Claims (1)

[Scope of Claims] 1. A power supply, a discharge tube that discharges by supplying power from the power supply, a resistance component that is inserted in series with the power supply and the discharge tube to adjust the discharge current, and a resistance component arranged around the outer periphery of the discharge tube. an electrode, a high-frequency oscillator that applies a high-frequency voltage to the electrode, and a high-frequency oscillator that detects the voltage at both tube ends of the discharge tube so that the voltage at both tube ends becomes a constant high voltage close to the power supply voltage. A gas laser oscillator equipped with a control circuit that controls oscillation output. 2. The gas laser oscillator according to claim 1, wherein the high-frequency oscillator is a variable output voltage oscillator, and the control circuit decreases or increases the output voltage of the oscillator in accordance with an increase or decrease in discharge current. 3. The gas laser oscillator according to claim 1, wherein the high-frequency oscillator is a variable frequency oscillator, and the control circuit decreases or increases the output frequency of the oscillator in accordance with an increase or decrease in discharge current.