JPH0332077A - Laser device - Google Patents

Abstract

PURPOSE:To simplify maintenance and increase a life by connecting an inductance circuit and a semiconductor switch in parallel with a laser load and disconnecting them during a current is fed to apply a voltage to the load to surely cause discharge. CONSTITUTION:An inductance circuit 6 and a semiconductor switch 12 are connected in parallel with a laser load 5. Then, when an ON signal is supplied to the gate G1 of the switch 12 and a charging command is provided, a high voltage power supply 1 operates to cause a charging current to flow through a capacitor 20. Then, when an oscillation command is provided and an ON signal is supplied to the gate G2 of the thyristor 18, the capacitor 20 starts discharging. A turn-off driving signal is supplied to the switch 12 when this discharging current reaches a maximum to effect high speed interruption of the switch 12. Then, a current with a high current-changing rate is produced and a reactor 14 applies a high voltage to the load 5. Thus, sure discharge operation can be obtained, maintenance can be simplified, and the life can be increased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser device that generates a discharge in a discharge space of a laser load to oscillate laser light.

[Conventional technology]

FIG. 4 is a circuit diagram showing the main circuit configuration of a conventional gas laser device of this type described in, for example, Japanese Unexamined Patent Publication No. 15083/1983. In FIG. 6, (υ is a high-pressure tIl source, (2
) is a thyratron, which is a switching element that turns on and off by controlling the voltage at a control terminal called a grid. (3) is a capacitor, (4) is a beam axle, and (5) is a laser load, inside of which there is a main discharge space (6) where the laser gas is excited by discharge, and a pre-ionization gap via the capacitor (7). (8) are formed.

Next, the operation will be explained. First, Thyratron (2)
A charging command is given to the high-voltage power supply (1) with . A voltage VL of the following formula is applied between the terminals of the laser load (5).

However, no discharge occurs in the main discharge space (6) as well as in the inductance ionization gap (8) of the reactor (4), and therefore, the capacitor (7) is not charged either.

After charging the capacitor (3) is completed, the thyratron (
When an oscillation command is given to 2) and it is turned on, the laser load (5
) jumps up, and first the pre-ionization gap (
8) is discharged. This allows thyratron (2) - capacitor (3) - capacitor (7) - preionization gap (
8) is formed, and a capacitor (3) is connected to this loop.
) flows and charges the capacitor (7).

Then, the time at which the charging voltage of this capacitor (7) reaches its peak is π', where l is the residual inductance of the I loop and C is the series capacitance of capacitors (3) and (7) included in the loop. At this time, a discharge occurs in the main discharge space (6) in the housing.

The energy stored in the capacitor (7) is mainly consumed in the main discharge space (6), and the energy stored in the capacitor (7) is mainly consumed in the main discharge space (6).
3) The energy remaining in the main discharge space (
6) and the reactor is consumed by the resistance valve of 4), thereby causing one discharge of the gas laser device! 1111
The work is completed.

Normally, it is necessary to repeat the above operation many times in order to increase the output of laser light.

[Problem to be solved by the invention]

The conventional gas laser device uses the thyratron (2) for current switching as described above. The thyratron (2) is equipped with a thermal IJ4i in mercury or argon gas, and there are issues such as wear of this electrode and deterioration of the sealed gas.
There were problems in that maintenance was complicated, the service life was short, and maintenance costs and thyratron renewal costs were high. In this case, it is possible to replace the thyratron with a semiconductor switch, but the ON time of the thyratron is on the order of 10 n5ec, and the laser load (
5), but the semiconductor switch is slow, on the order of 1 gsec, and is not suitable for use as a laser WX source.

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to obtain a laser device that is easy to maintain and has a long life by making it possible to apply a semiconductor switch.

[Means and effects for solving the problem] A laser device according to the present invention includes an inductance circuit having an inductance element and a self-extinguishing semi-V1. and a switch are connected in parallel with the laser load, and a drive circuit first supplies current to the semiconductor switch, and when energized, the semiconductor switch is cut off to generate a high voltage in the laser load.

〔Example〕

FIG. 1 is a circuit diagram showing the main circuit configuration of a gas laser device according to an embodiment of the present invention.
5) are conventional and opposite, respectively high pressure l! source and laser load. However, in FIG. 1, the lower terminal of the high voltage power supply (1) is the positive electrode side. Also, laser load (5)
A first electrode (9), a second electrode (g), and a third electrode (6) are provided with a discharge space (6) in between.

03 is a self-extinguishing semiconductor switch capable of high-speed shutoff such as a static induction thyristor, cLl is a diode connected anti-parallel to the semiconductor switching □, α◆ is an inductance element, and (1G is a capacitor) An inductance circuit Qθ is constructed by a series body of this reactor I and αE and a capacitor (to).

And aη is a drive circuit, which is connected in series with the high voltage power supply (1), the thyristor μs connected in parallel with this high voltage power supply H (13), the diode CIIJ connected in anti-parallel to this, and the high voltage power supply (1). It is composed of a capacitor (1) with a capacitor (1) and a capacitor (1).

Next, the operation will be explained according to the time chart shown in FIG. First, a charging command is issued at time T1, but an ON signal has already been applied to the gate G1 of the semiconductor switch O. The high-voltage power supply T1) of the drive circuit α is activated by the charging command to raise its output voltage. This allows the high voltage llt source (11 - diode (to) - react IL/
(B) - Charge L to the I loop which is 186 at (to the capacitor)
IE current flows and the voltage across the terminals of the capacitor (7) is the first
ti! shown in the figure! The voltage gradually rises to a value determined by the high voltage source 11E+1) at time T2, and after charging is completed, the voltage value is maintained at a constant value.

Thereafter, at time T3, an oscillation command is issued and an ON signal is given to the thyristor gate G2. As a result, the thyristor α-condenser reactor (b)-
A semiconductor switch loop is formed and the capacitor starts discharging. At time T4 when this discharge current has almost reached its maximum, an OFF signal, that is, a turn-off drive signal is applied to the semiconductor switch y-□□□.

Due to the high-speed shutoff of the semiconductor SWINOH PQ2, the capacitor (
The discharge current in 7) is commutated from the semiconductor switch (6) to the inductance circuit αG, and due to its high current time change rate, a high voltage is generated due to the inductance of αG and is applied to the laser load (5). .

As a result, a corona discharge occurs between the second electromagnetic image aO and the third electrode (b) inside the laser load (5), and this becomes preliminary ionization, and immediately the first electrode ( 9) and the third a (+1), and laser oscillation is performed.

When the current of the laser load (5) becomes zero at time T5, from then on, the discharged KW flow of the capacitor (4) becomes the capacitor (A) -
It will flow through an I loop consisting of diode 09 - diode 0 - reactor 1. Then, at time T6 while this diode (2) is energized, the semiconductor switch y
The ON signal is applied again to the gate Gl of ``O'' to set it as a reset state.

The voltage across capacitor 4 is reversed while this diode 03 is energized, and returns to its original polarity. At time T7, the voltage reaches its maximum value and the discharge current becomes zero, when the semiconductor switch (
2) and the thyristor are both in the OFF state, so
Thereafter, no discharge I-rape is formed, and the voltage of the capacitor (1) remains constant. The voltage is started from the voltage after the end of the above-mentioned operation. In addition, when completely stopping the laser device, turn on the thyristor after the final discharge operation is completed.
A signal is applied to form a discharge loop to cause stored energy to be dissipated by a resistance valve within the loop.

In this example, the high speed turn-off characteristic of the semiconductor switch 0 is used to generate a high current time change rate, so a high voltage sufficient for the discharge operation of the laser load (5) is obtained, and the casing is Since it is a semiconductor switch, it can be easily maintained and has a long life even if it is operated frequently.

In the above explanation, the reactor shaft and @ were treated as circuit elements, but by utilizing the so-called residual inductance component that is substantially present depending on the specific wiring structure, the reactor shaft and @ are treated as circuit elements. It is also possible to omit the configuration.

FIG. 3 shows another embodiment of the present invention, in which a constant current source is used as the power source for the MA dynamic circuit aη.

Prior to discharging, first, a direct current is caused to flow through the semiconductor switch f-(2) by this constant current source @, and when an oscillation command is issued, the semiconductor switch 0 is shut off at high speed, and the same as in the above embodiment is carried out. This current is commutated to the inductance circuit CI6 to generate a high voltage.

〔Effect of the invention〕

As described above, in this invention, an inductance circuit and a self-extinguishing semiconductor switch are each connected in parallel with a laser load, and the semiconductor switch is cut off when energized to apply voltage to the laser load. Therefore, a reliable discharge operation can be obtained, maintenance is simple, and the life span is increased, thereby realizing an economical and highly reliable laser device.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the main circuit configuration of a gas laser device according to an embodiment of the present invention, FIG. 2 is a time chart explaining its operation, and FIG. 3 is a circuit diagram showing the main circuit configuration of a gas laser device according to another embodiment of the present invention. FIG. 4 is a circuit diagram showing the main circuit configuration of a conventional gas laser device. In the figure, (5) is the laser load, <6) is the discharge space,
(6) is a semiconductor switch, 0η is an inductance element, αQ is an inductance circuit, (b)
is the drive circuit. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A laser load having a discharge space formed therein, an inductance circuit having an inductance element and connected in parallel with the laser load, a self-extinguishing semiconductor switch connected in parallel with the laser load, and the semiconductor switch. A laser device comprising: a drive circuit that supplies current in the forward direction to the semiconductor switch and applies a voltage to the laser load to generate a discharge in the discharge space by cutting off the semiconductor switch when the current is applied.