JPH051987B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to laser devices, particularly high repetition rate, rare gas halogen excimer lasers and metal vapor laser devices. "Prior Art and Problems to be Solved by the Invention" One of the circuit systems for rare gas halogen excimer lasers and metal vapor lasers is a capacitive transfer type. In this capacitance transfer type, the charge charged in the first capacitor is rapidly transferred to the second capacitor by a high-speed switch, and this is used as discharge power for the laser. However, in the conventional type, when the laser discharge is unstable, the high-speed switch is affected by the instability and may not operate stably. In such a case, the high-speed switch does not recover to the OFF state and turns OFF.
If the condition persists, there is a possibility that this high-speed switch etc. may be damaged. Furthermore, since the noise power in the high-speed switch is too large, this noise enters the control system, resulting in a lack of stability. The present invention seeks to eliminate such conventional drawbacks. ``Means for Solving the Problems'' The present invention provides a carrier-controlled inverter power source that can be stopped periodically, a first capacitor that is charged by the power source, and a second capacitor that supplies discharge power to the laser. a capacitor, a high-speed switch that quickly charges the charge of the first capacitor to a second capacitor when the power supply is stopped, and a high-speed switch drive circuit that operates the high-speed switch;
It consists of a control circuit that periodically stops the above power supply by carrier control and activates the high speed switch drive circuit during the stop, thereby ensuring stability by ensuring the operation of the high speed switch. The present invention is characterized in that an optical control means is provided between the control circuit and the high-speed switch drive circuit to eliminate the influence of noise on the pulse generation circuit. "Operation" With the above configuration, the carrier control inverter power supply is periodically stopped by the control circuit, and
The high-speed switch is turned on through the high-speed switch drive circuit when it is at rest. Therefore, during operation of the carrier controlled inverter power supply, the first capacitor is charged and
During rest, the charge is rapidly transferred to the second capacitor through a high speed switch, and when the potential reaches the laser firing voltage, discharge begins, causing the laser to start. Since the optical control means is used as described above, noise in the high-speed switch does not enter the control circuit and the stability is not disturbed. "Example" FIG. 1 shows a circuit according to an example of the present invention,
In the figure, 1 is a carrier-controlled inverter power supply that can be stopped periodically, C ₁ is a first capacitor charged by the power supply, and C ₂ is
a second capacitor that supplies discharge power to the laser 2; 3 a high-speed switch that charges the first capacitor to a second capacitor when the power supply is stopped; 4 a high-speed switch that operates the high-speed switch; A drive circuit 5 is a control circuit that periodically stops the power supply by carrier control and operates the high speed switch drive circuit during the stop, and is connected by an optical fiber 6 between the control circuit and the high speed switch drive circuit. Light control measures are in place to 7 is the second capacitor
This is a pulse compression circuit for charging _C2 with rapid pulse charge. The carrier control inverter power supply 1 includes an SCR 11 that introduces and rectifies 3-phase AC200V, an LC filter 13 that smoothes the rectified output, a variable constant voltage control circuit 12 that controls the SCR, and a DC that converts the smoothed DC back into AC. /AC bridge inverter 1
4. A pulse output circuit 15 provided to control the DC/AC bridge inverter, a high voltage transformer 16 that boosts the output of the DC/AC bridge inverter to about 20KV, and a total circuit that rectifies the output of the high voltage transformer. It consists of a wave rectifier 17. The high speed switch 3 consists of a thyristor, thyratron, etc. When using a thyratron, a small inductance L ₁ is inserted in series with the first capacitor C ₁ as shown in FIG. 3 in order to alleviate the start-up shock. In the case of a thyristor, etc., the inductance _L1 is not necessary because the rise time is rather slow. The control circuit 5 includes a carrier generation circuit that supplies a carrier signal to the pulse output circuit 15, and periodically suspends the output of the pulse output circuit 15.
That is, it comprises a carrier control circuit that periodically stops the carrier control inverter power supply 1, and a timing signal generation circuit that sends a timing signal to the high speed switch drive circuit 4 when the carrier control circuit stops.
Furthermore, the rest time and period in the carrier control circuit can be changed freely. The pulse compression _circuit 7, as _shown in _FIG . The capacitor C is set so that it saturates rapidly at the point where the introduction of energy from ₁ is almost finished. Note that FIG. 3 shows an example in which a thyratron is used as the high-speed switch 3, and therefore, as described above, the inductance _L1 is used. The operating principle of this pulse compression circuit 7 is as follows. First, when the high-speed switch 3 is turned on, the electric charge of the first capacitor _C1 is transferred (charged) to the third capacitor _C3 . At the beginning of this charging, since the saturated inductance _L2 is large (FIG. 4a), almost no current _i1 flows through the saturated inductance, and the potential at point _P1 rises (FIG. 4b). At the point when the third capacitor _C3 is almost finished charging, the circuit quickly saturates and the third capacitor C3 is almost finished charging.
A current i ₁ flows from C ₃ to the second capacitor C ₂ (see figure c), the second capacitor C ₂ is rapidly pulse-charged, and the potential at point P ₂ rapidly increases, causing a discharge in the laser 2. (Figure d). In this case, compression of about 5 times is possible in one stage (t ₁ /t ₂ ≦5). Next, the operation of the entire device will be explained. Carrier control inverter power supply 1 introduces AC 200V three-phase, which is connected to SCR 11 and LC filter 1.
3. Convert to DC120-250V with variable constant voltage control circuit 12. Further, the carrier signal shown in FIG. 2A from the carrier signal generation circuit is controlled in the pulse circuit 15 by the carrier control signal shown in FIG. This pulse output operates the DC/AC bridge inverter 14, and when the pulse output is Ton (FIG.
AC voltage based on 250V and OV at Toff
This is boosted by a high-voltage transformer 16 to an AC voltage of about 20 KV at Ton (OV at Toff) as shown in D of the figure, and rectified by a full-wave rectifier 17 to produce the output shown in F of the figure. With the output of this carrier control inverter power supply 1,
At the time of Ton, the first capacitor _C1 is charged. Furthermore, at Toff, the high-speed switch drive circuit 4 is operated through the optical control means including the optical fiber 6 by the timing signal shown in FIG. When this high-speed switch 3 is turned on, the electric charge in the first capacitor _C1 rapidly moves to the second capacitor _C2 via the pulse compression circuit 7, and when the potential reaches the laser discharge starting voltage, discharge begins. , performs laser oscillation. The laser voltage waveform and laser output in this laser oscillation are as shown in FIGS. In other words, it is repeated every cycle Tsec. The formula for adjusting the pause time is as follows.

【table】

[Table] 〓8〓
As described above, by changing Non and Noff, the duty 12.5 to 87.5%, that is, the OFF time Toff changes under the above conditions, and the pause time can be adjusted. In addition, as shown in Figure 2
Tdelay is a fixed time that takes into account switch element delay and the like. "Effects of the Invention" According to the present invention, the control circuit periodically stops the carrier control inverter power supply, and
Turn on/off the high speed switch only during the downtime
Therefore, the general switch can be turned on and off accurately without being affected by the carrier control inverter power supply.
It turns OFF and reliably returns to the OFF state, thus ensuring stable laser discharge and preventing damage to high-speed switches and the like. Furthermore, since a light control means is provided between the control circuit and the high speed switch drive circuit, noise generated by the high speed switch is blocked by this light control means.
It does not penetrate into the control circuit and therefore
The pulse generation circuit in the carrier control inverter power supply is not adversely affected, and highly efficient and highly stable operation can be achieved. Thus, the stop time of the carrier control inverter power supply can be freely changed, and the repetition period can be freely changed.

[Brief explanation of the drawing]

The drawings show examples of the present invention; FIG. 1 is a circuit diagram, FIG. 2 is a waveform diagram of each part of the circuit, FIG. 3 is a circuit diagram of the main part, and FIG. 4 is a diagram of the circuit. It is a waveform diagram of each part. DESCRIPTION OF SYMBOLS 1...Carrier control inverter power supply, 2...Laser, 3...High speed switch, 4...High speed switch drive circuit, 5...Control circuit, 6...Optical fiber, _C1 , _C2 ...Capacitor.

Claims (1)

[Claims] 1. A carrier-controlled inverter power supply that can be stopped periodically, a first capacitor charged by the power supply, a second capacitor that supplies discharge power to the laser, and a first capacitor that is connected to the first capacitor when the power supply is stopped. a high-speed switch that charges a second capacitor at high speed, a high-speed switch drive circuit that operates the high-speed switch, and control that periodically suspends the power supply by carrier control and activates the high-speed switch drive circuit during the suspension. What is claimed is: 1. A laser device comprising a circuit, and comprising an optical control means between the control circuit and the high-speed switch drive circuit.