JPH03203277A - Pulse gas laser oscillation apparatus - Google Patents

Abstract

PURPOSE:To surely remove impurities without using a large-sized blower even when the repetition number of a pulse laser beam is increased and to generate a main electric discharge by a method wherein a part which is narrower than a circulation route to a part between a second electrode and a third electrode is formed in a circulation route to a part between a first electrode and the third electrode on the upper-stream side. CONSTITUTION:Individual air-pressure adjustment pieces 20, 21 are installed at the inside of a gas laser tube 1. The air-pressure adjustment pieces 20, 21 are arranged in positions which are situated on the upper-stream side of the flow of a gas as viewed from a first electrode up to a third electrode 2 to 4, which are parallel along the flow direction of the gas by using a blower 8 and which correspond respectively to the first electrode 2 and the third electrode 4. That is to say, the air-pressure adjustment piece 20 is installed on the inner wall of the gas laser tube 1, and the air-pressure adjustment piece 21 is installed so as to be continued to the third electrode 4. Respective opposite face sides of the individual air-pressure adjustment pieces 20, 21 are formed in protruding shapes and narrow the circulation route of the gas. Thereby, even when the repetition number of a pulsed laser beam is increased, it is possible to surely remove impurities without using a large-sized blower or the like and to generate a main electric discharge.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a pulsed gas laser oscillation device.

(Prior art) Figure 2 shows the constituent countries of a pulsed gas laser oscillation device.
Inside the gas laser tube 1, a first electrode 2 and a second electrode 3 are disposed facing each other.
A third electrode 4 is arranged between and. As shown in FIG. 3, this third ffi pole 4 has a large number of holes 5 formed therein so that charged particles such as electrons and ions can pass therethrough.

By arranging the third electrode 4 in this way, the first discharge space A is formed by the first electrode 2 and the third electrode 4, and the second discharge space A is formed by the second electrode 3 and the third electrode 4. B is formed. A discharging capacitor CPl+C112 is connected between the first electrode 2 and the third electrode 4, and a large number of glass tubes 7 having conducting wires 6 therein are arranged on the surface of the 's1 electrode 2. . These conducting wires 6 are commonly connected and grounded. Moreover, the second electrode 3 and the third electrode 4
Discharging capacitors Cp31 to Cn4 are connected between them, and charging coils L, , L are connected to the third electrode 4.
2 are connected. A crystal piezoelectric element [H, V] is connected to the second electrode 3 via a diode D and a resistor R1. Furthermore, a blower 8 is arranged inside the gas laser tube 1. On the other hand, the charge/discharge circuit 9 includes a crystal type piezoelectric RH.
, V are provided, and a resistor,
A switch 1o and a capacitor Ca are connected in parallel via R2, and a charging coil L3 is connected to the capacitor Ca in parentheses. A connection point between the capacitor Ca and the charging coil L is connected to the first electrode 2.

With such a configuration, when the switch 10 is closed, the electric charge stored in the charging/discharging capacitor Ca is transferred to each discharging capacitor CLLL+Cp2. As a result, each discharging capacitor CD1r Cp2 is charged, and the voltage applied to these discharging capacitors cDlrC22 increases rapidly. At this time, the voltage applied between each conducting wire 6 and each glass tube 7 becomes high, and corona discharge occurs between these conducting wires 6 and glass tubes 7. Due to this corona discharge, the discharge space A between the first electrode 2 and the third electrode 4 is ionized by fOI, and subsequently, a trigger discharge occurs between the first electrode 2 and the third electrode 4. Due to this trigger discharge, a large number of charged particles such as electrons and ions are supplied to the discharge space B from each company 5 of the third electrode 4.

In this state, a high voltage is applied between the second electrode 3 and the third electrode 4 from the crystalline piezoelectric [H, V], so the short wavelength light generated by supplying and discharging a large amount of front particles is triggered. As a result, the gas laser medium between the second electrode 3 and the third electrode 4 is excited, and thereby a main discharge is generated between the second electrode 3 and the third electrode 4.

Thus, optical resonance occurs in the optical resonator and a pulsed laser beam is output.

When a main discharge occurs between the second electrode 3 and the third electrode 4 as described above, impurities such as spatter are generated by this main discharge. In order to remove these impurities, the gas between the first electrode 2 and the second electrode 3 is caused to flow by driving the blower 8.

In this way, the gas is flowing between the first electrode 2 and the second Ma electrode 3, but as the number of repetitions of the pulsed laser beam is increased, the interval between laser beams is shortened, so the gas flow rate must be increased. The next main discharge occurs in a state where impurities remain between the first electrode 2 and the second voltage base 3. Therefore, in order to increase the gas flow rate, the blower 8 and its attached devices become larger.

(Problems to be Solved by the Invention) As described above, if the number of repetitions of the pulsed laser beam is increased, the size of the blower and its auxiliary equipment will increase in order to increase the gas flow velocity.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a pulsed gas laser oscillation device that can remove impurities and generate a main discharge without using a large blower even when the number of repetitions of a pulsed laser beam increases. .

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a gas laser tube filled with gas as a laser medium, first and second electrodes disposed opposite to each other in the gas laser tube, and the first and second electrodes. comprising a breathable third electrode disposed between the two electrodes, and a circulation means for circulating gas within the gas laser tube and flowing between the first and third electrodes and between the second and third electrodes, respectively; Charged particles are generated between the first electrode and the third electrode, and the charged particles are supplied between the second electrode and the third electrode to generate a main discharge between the second electrode and the third electrode. In the pulsed gas laser oscillation device for generating pulsed gas, a flow path between the first electrode and the third electrode on the upstream side of the flow is formed with a narrower portion than a flow path between the second electrode and the third electrode. This is a pulsed gas laser oscillation device that attempts to achieve the above object.

(Function) By providing such a means, the atmospheric pressure between the first electrode and the third electrode in the gas laser tube is adjusted to be lower than the atmospheric pressure between the second electrode and the third electrode by the atmospheric pressure adjusting means. ,
As a result, the gas between the second electrode and the third electrode passes through the third electrode due to the pressure difference between the electrodes, flows into the space between the first electrode and the third electrode, and is removed.

(Example) Hereinafter, an example of the present invention will be described with reference to a block diagram of a pulsed gas laser oscillation device shown in Figure 1. In addition,
Components that are the same as those in FIG. 2 are given the same numbers, and detailed explanation thereof will be omitted.

There is a lot of air inside the gas laser tube 1! An f adjustment piece 20°21 is provided. The air pressure adjustment pieces 20 and 21 are arranged on the upstream side of the gas flow when viewed from the first to third electrodes 2, 3.4, parallel to the gas flow direction by the blower 8, and on the first side. They correspond to the electrode 2 and the third electrode 4, respectively. That is, the air pressure adjustment piece 20 is provided on the west wall of the gas laser tube 1, and the air pressure adjustment piece 21 is provided so as to be continuous with the third electrode 4.
21 are each formed in a convex shape on the opposing surface side to narrow the gas flow path.

With such a configuration, when the switch 10 is closed, the electric current stored in the charging/discharging capacitor Ca is transferred to each discharging capacitor Cpl+Cp2, and each discharging capacitor CPl+Cp2 is charged and discharged. The voltage applied to the capacitor Cpl+Cp:l increases rapidly. In this state, the voltage applied between each conducting wire 6 and each glass tube 7 increases, and corona discharge occurs between these conducting wires 6 and glass tubes 7. The discharge space A between the first electrode 2 and the third electrode 4 is pre-ionized by this corona discharge, and subsequently a trigger discharge occurs between the first electrode 2 and the third electrode 4. Due to this trigger discharge, a large number of charged particles such as electrons and ions are supplied to the discharge space B from the hole 5 of the third electrode 4.

In this state, a high voltage is applied between the second electrode 3 and the third electrode 4 from the high voltage power supplies H and V, so the supply of a large amount of charged particles and the short wavelength light caused by the discharge serve as a trigger. The gas laser medium between the second electrode 3 and the third electrode 4 is excited, thereby generating a main discharge between the second electrode 3 and the third electrode 4.

(Thus, optical resonance occurs in the optical resonator and a pulsed laser beam is output.

On the other hand, the gas inside the gas laser tube 1 is being circulated by the blower 8 being driven. In this case, the gas blown by the blower 8 flows between the first electrode 2 and the third electrode 4 through the air pressure adjustment pieces 2(') and 21, and along with it flows onto the concave surface of the air pressure adjustment piece 21. It flows between the second electrode 3 and the third electrode 4 along the line. At this time, since the gas flow path is narrowed by each air pressure adjustment piece 20, 21, the flow velocity between the first electrode 2 and the third electrode 4 is higher than that between the second electrode 3 and the gauze 3 electrode 4. The flow velocity is greater than that between the two. Note that the flow rates are reversed.

Therefore, the 11th! I! Since the atmospheric pressure between the pole 2 and the third electrode 4 is lower than that between the second electrode 3 and the third electrode 4, the gas flowing between the second electrode 3 and the ff13 electrode 4 is It flows through the hole 5 of the third electrode 4 between the first electrode 2 and the third electrode 4 .

Therefore, the impurities generated by the main discharge between the second electrode 3 and the third electrode 4 are transferred between the first electrode 2 and the third electrode 4 at the flow rate between the first electrode 2 and the third electrode 4. Inflow. As a result,
Impurities are quickly removed, making it possible to generate the next main discharge quickly.

In this way, in the above embodiment, the air pressure between the first electrode 2 and the third electrode 4 in the gas laser tube is controlled by each air pressure adjustment piece.
0.21, the gas flow rate between the first electrode 2 and the third electrode 4 is adjusted to be lower than the atmospheric pressure between the third electrode 4 and the second electrode 3. Since the flow rate was made faster than the flow rate between the second electrode 3 and the third electrode 4, the gas between the second electrode 3 and the third electrode 4 passes through the third electrode 4 and flows into the space between the first electrode 2 and the third electrode 4. Can be removed quickly. Therefore, the number of repetitions of the pulsed laser beam can be increased without increasing the size of the blower 8 and its attached devices. Moreover, the life of the blower 8 can be extended.

Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof. For example, each pressure side January'20.21 may have another shape instead of a convex shape, as long as the pressure in the discharge space A is lower than the pressure in the discharge space B. Further, the means for pre-ionization may be replaced by a UV method or an X-ray method.

[Effects of the Invention] As detailed above, according to the present invention, even if the number of repetitions of the pulse 0 laser beam increases, impurities can be reliably removed and a main discharge can be generated without using a large blower or the like. Pulsed gas laser oscillation equipment can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a pulsed gas laser oscillation device according to the present invention, FIG. 2 is a block diagram of a conventional device, and FIG.
The figure is an external view of the third electrode. DESCRIPTION OF SYMBOLS 1... Gas laser tube, 2... First electrode, 3... Second electrode, 4... Third electrode, 6... Leading wire 6.7...
Glass tube, 8...Blower, 9...Charging/discharging circuit, 20
．． 21...Atmospheric pressure adjustment piece.

Claims (1)

[Claims] a gas laser tube filled with gas as a laser medium; first and second electrodes disposed oppositely within the gas laser tube;
A breathable third electrode is arranged between the first and second electrodes, and the gas is circulated within the gas laser tube between the first and third electrodes and between the second electrode and the third electrode. and a circulation means for respectively circulating charged particles between the first electrode and the third electrode,
In the pulsed gas laser oscillation device that supplies the charged particles between the second electrode and the third electrode to generate a main discharge between the second electrode and the third electrode, the charged particles are supplied between the second electrode and the third electrode. A pulsed gas laser oscillation device characterized in that a flow path between the first electrode and the third electrode is narrower than a flow path between the second electrode and the third electrode.