JPH0413872B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a silent discharge pumped laser device, and particularly to an improvement in a power supply circuit.

[Conventional technology]

As a conventional silent discharge excitation laser device, there is one shown in FIG. 1, for example. In this figure, the output side of a power source 1 is connected to a pair of electrodes 2A and 2B whose surfaces are covered with a dielectric material. These electrodes 2
A, 2B are arranged in a laser oscillator 4 filled with a laser medium gas 3, and these electrodes 2A, 2B
A silent discharge 5 is generated in between.

When the total reflection mirror 6 and the partial transmission mirror 7 are arranged to face each other with the silent discharge 5 in between, laser oscillation occurs and laser light 8 is output.

Next, FIG. 2 shows a cross section of the electrode part in FIG. are connected to the outputs of each. When the output voltage of this power source 1 is increased, a silent discharge 5 is generated between the electrodes 2A and 2B as described above.

Further, FIG. 3 shows an electrical equivalent circuit of the electrodes 2A and 2B where the silent discharge 5 is generated.

In this figure, 11A and 11B are dielectric bodies 10
A and 10B are the capacitances, and 13 is the equivalent resistance of the silent discharge 5.

[Problem that the invention seeks to solve]

However, the above conventional techniques have the following problems.

Generally, the output of power supply 1 is an alternating current of 10KHz or higher, and the output current of power supply 1 is the capacitance of dielectric material 11
It is determined by the series impedance of A, 11B and the equivalent resistance 13. Therefore, if the impedance of the dielectric capacitances 11A and 11B is high, the output current of the power source 1 will not flow, and the discharge power input to the equivalent resistance 13 will be limited.

There is also another problem in that the power factor of the output current deteriorates and a large capacity power source 1 is required.

This invention was made to eliminate the problems of the prior art as described above, and by connecting a reactor within the power supply circuit to form a series resonant circuit, the maximum power from the power supply can be obtained as silent discharge power. It is an object of the present invention to provide a high-output silent discharge excitation laser device that can be extracted.

[Means for solving problems]

The present invention connects a reactor to the low-voltage side of a step-up transformer in a power supply circuit, and uses the inductance of this reactor and step-up transformer to suppress series resonance due to the frequency of input power with respect to the capacitance of the electrode dielectric. It is characterized by the fact that it occurs.

[Effect]

According to the present invention, the power supply circuit enters a series resonance state, and the load impedance becomes a resistance component. Therefore, power from the power supply is applied to the load with a good power factor.

The inductance of the reactor is that the reactor is connected to the low voltage side of the step-up transformer, and
Since the leakage reactance of the step-up transformer is utilized, a relatively small capacity one is sufficient.

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the same reference numerals are used for the same components as in the prior art described above.

First, the basic principle of the present invention will be explained with reference to FIGS. 4 and 5. In Fig. 4, 14 is a reactor, and this reactor 1
4 is connected in series with electrodes 2A and 2B.

FIG. 5 is an electrical equivalent circuit of FIG. 4.
Here, the reactor 14 and each capacitance 11
If the value of reactor 14 is chosen so that the series circuit of A and 11B resonates in series with the output frequency of power supply 1, then
The series impedance of the reactor 14 and the capacitances 11A and 11B becomes zero, and as shown in FIG. 6, the load on the power supply 1 is only the silent discharge equivalent resistance 13, and the output voltage of the power supply 1 is entirely the silent discharge voltage. Therefore, the maximum power is input from the power source 1 to silent discharge.

As described above, the present invention utilizes the phenomenon of series resonance. Examples of the present invention will be described below.

Since silent discharge generally requires high voltage, a step-up transformer 16 is often used as shown in FIG. 7, but if the reactor 14 is connected to the low voltage side of the step-up transformer 16, the inductance of the reactor 14 is The value can be even smaller than that of the electrodes 2A and 2B shown in FIG. 4, which are directly connected.

The reactor 14 is connected to the electrode 2 from the power source 1.
The inductance of the wiring up to A and 2B and the leakage inductance of the step-up transformer 16 are included as necessary.

FIG. 8 shows the equivalent impedance on the primary side of the step-up transformer 16.

Here, if the turns ratio of the secondary side to the primary side of the transformer is n, then the capacitance 17 is the capacitance 11
The resistance 18 is n ² times the series capacitance of A and 11B, and 1/n ² of the equivalent resistance 13. Each of these values
If n ² C, R/n ² , the inductance of the reactor 14 is L, and the output voltage of the power supply 1 is E, the power W consumed by the resistor 18 is W = (E/jωLR/n ² +1/jωn ^2c )
²・R/n ² =RE ² /{R/n+j(ωnL−1/ωnc)} ²
…(1) It can be expressed as:

At this time, the condition for the maximum power W is when the imaginary part of the denominator (ωnL-1/ωnc)=0.

Therefore, when the turns ratio n is n=1/ω√Lc...(2), the power W is W=n ² E ² /R...(3).

Moreover, when the above equation (2) is rewritten, ωL=1/ωn ² c, which satisfies the condition for series resonance between the reactance L and the capacitance n ² c. Therefore, the series impedance of the capacitance 17 of the reactor 14 becomes zero, and FIG. 8 can be rewritten as shown in FIG. 9. That is, by selecting a value such that the turns ratio n=1/ω√Lc, the reactor 14 and the capacitances 11A and 11B can be made to resonate in series.

As explained above, according to this embodiment, a reactor is connected to the low voltage side of the step-up transformer in the power supply circuit, and the total reactance of the reactor, the leakage reactance of the step-up transformer, and the electrode Since series resonance is performed with respect to the capacitance of the dielectric material, the power of the power source is effectively extracted as a laser output, and the power factor is also improved.

Furthermore, the capacity of the power supply and reactor is reduced,
The device can be made smaller.

Note that the present invention is not limited to the above-mentioned embodiments, and for example, the inductance of the wiring from the power source 1 to the electrodes 2A and 2B may be included as the reactance for performing series resonance.

〔Effect of the invention〕

As explained above, according to the present invention, a reactor is connected to the low voltage side of the step-up transformer, and series resonance is caused by the inductance of the reactor and the step-up transformer with respect to the capacitance of the electrodes. It has the following effects.

Power from the power source is effectively input as silent discharge power, and a good laser output can be obtained.

Power factor is improved.

The power output required to obtain the same laser output is reduced, and the power capacity can be reduced.
The device can be made smaller.

The leakage inductance of the step-up transformer is effectively utilized and the capacity of the reactor is reduced.

Setting the circuit constants that satisfy the conditions for series resonance,
This can be easily applied to various step-up transformers.

[Brief explanation of drawings]

Figures 1 to 3 each show a conventional laser device, with Figure 1 being a diagram explaining its configuration, Figure 2 being a sectional view, Figure 3 being an electrical equivalent circuit diagram, and Figure 4 being an electrical equivalent circuit diagram. 6 through 6 respectively show the basic configuration of the laser device according to the present invention, FIG. 4 is a diagram explaining the principle, FIG. 5 is an electrical equivalent circuit diagram, and FIG. 6 is an equivalent diagram. The diagrams illustrating the operation of the circuit and FIGS. 7 to 9 are configuration diagrams illustrating embodiments of the present invention, respectively. In the figure, 1 is a power supply, 2A, 2B are electrodes, 3
is a laser medium gas, 4 is a laser oscillator, 5 is a silent discharge, 6 is a total reflection mirror, 7 is a partially transmission mirror, 8 is a laser beam, 9A, 9B are conductors, 10A, 10B are dielectrics, 11A, 11B are dielectrics 13 is the equivalent impedance of silent discharge, 14 is the reactor, 16 is the step-up transformer, and 17 and 18 are the equivalent impedances of the electrodes seen from the primary side of the step-up transformer 16. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of Claims] 1. Silent discharge is performed by applying AC power boosted by a step-up transformer between electrodes that are placed facing each other in a laser medium gas and have a dielectric material provided on their surfaces. Therefore, in the silent discharge excitation laser device that excites the laser medium gas and obtains a laser output, a reactor is connected to the low voltage side of the step-up transformer, and the inductance of this reactor and the leakage inductance of the step-up transformer are respectively utilized. A silent discharge excited laser device, characterized in that circuit constants are set so that series resonance due to the frequency of the alternating current power occurs with respect to the capacitance of the dielectric.