JPH0263177A - Laser device - Google Patents

Abstract

PURPOSE:To reduce an inactivated region of laser excitation and effectively take out laser excitation energy to the outside by locating the center of a discharge region upstream laser light. CONSTITUTION:The center 6 of an rf discharge region 5 is adapted to locate upstream a laser gas flow 3 by a distance X compared with the center 8 of laser light 7. The distance X(mm) between the both centers is set to satisfy a relation 0< X<=DV/P where D is the outer diameter of the laser light 7, V(m/s) is a flow rate of the laser gas flow 3, and P(Torr) is gas pressure. Hereby, an invalid region 9 of laser excitation in the rf discharge region 5 can sharply be reduced or eliminated. Further, if the displacement X of an output position of a laser beam satisfies a relation 0< X<=D, a laser output can be increased compared with a case with X=0.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a three-axis orthogonal type laser device in which the direction of a discharge electric field, the direction of a laser gas flow, and the direction of a laser optical axis are orthogonal to each other. be.

(Prior Art) FIG. 4 shows an example of a three-axis orthogonal laser device used in various laser processing, in which the direction of the discharge electric field, the direction of the laser gas flow, and the direction of the laser optical axis are orthogonal to each other. That is, dielectrics 2a and 2b are provided inside a pair of discharge electrodes 1a and 1b arranged to face each other in order to equalize the discharge.
A laser gas flow 3 is configured to flow between the dielectrics 2a and 2b.

Furthermore, a high frequency power source 4 having a generation frequency of 1 MH2 to 100 MH2 is connected between the discharge electrodes 1a and 'lb, and the operation of this high frequency power source 4 causes the discharge electrodes 1a and 'lb to be connected to each other. , 1b, a high-frequency discharge is lit in a rectangular region 5, and within this high-frequency discharge region 5,
Laser excitation occurs. The energy excited in this way can be extracted to the outside as light.

At this time, in order to perform a laser firing operation or take out laser light, the center 6 of the high frequency discharge region 5 and the center 8 of the circular laser light 7 are configured to coincide.

(Problems to be Solved by the Invention) However, in the conventional laser device having the above configuration, there were problems to be solved as described below.

That is, since the center 6 of the high-frequency discharge region 1fA5 and the center 8 of the laser beam 7 are made to coincide with each other, in the quadrangular discharge region 5, the laser excitation is disabled on the downstream side of the laser gas flow 3 of the circular laser beam 7. Region 9 is formed.

Therefore, all of the laser-excited energy in the high-frequency discharge region 5 cannot be extracted to the outside as the energy of the laser beam 7, and the volume utilization efficiency of the laser becomes low, and the energy efficiency of the laser extracted to the outside becomes low. was getting lower.

The present invention was proposed to eliminate the above-mentioned drawbacks, and its purpose is to provide a laser device that can efficiently extract energy excited by laser in a discharge region to the outside as laser light energy. be.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a three-axis orthogonal laser device in which the direction of the discharge electric field, the direction of the laser gas flow, and the direction of the laser optical axis are orthogonal to each other. Compared to the center of the laser beam,
It is configured to be located upstream of the laser gas flow by ΔX, and the distance between the two centers ΔX (mm) is such that the outer diameter of the laser beam is D (mm) and the flow velocity of the laser gas flow is v [m/
s), when gas pressure is P (torr), O<ΔX≦
It is set to satisfy DV/P.

(Function) According to the laser device of the present invention, by configuring the center of the discharge region to be located upstream of the laser gas flow by ΔX compared to the center of the laser beam, the ineffective region of laser excitation can be reduced. The laser excitation energy can be efficiently extracted to the outside.

(Example) Hereinafter, an example of the present invention will be specifically described based on FIGS. 1 and 2. Incidentally, the same members as those of the conventional type shown in FIG. 4 are given the same reference numerals, and the description thereof will be omitted.

In this embodiment, as shown in FIG. 1, the center 6 of the high frequency discharge region 5 is ΔX
The laser gas flow 3 is located upstream of the laser gas flow 3.

The distance ΔX (mm) between the two centers is defined by the outer diameter of the laser beam 7 being D (mm) and the flow velocity of the laser gas flow 3 being v (mm).
/s), and the gas pressure is P (torr), O<Δ
It is set to satisfy X≦Dv/P.

In the laser device of this embodiment having such a configuration, as shown in FIG. 1, the center 6 of the high frequency discharge region 5 is
Compared to the center 8 of the laser beam 7, the laser gas flow 3 is increased by ΔX.
By configuring it to be located upstream of the laser excitation region ti9 in the high frequency discharge region 10.5, the ineffective region ti9 of laser excitation can be significantly reduced or eliminated. However, at this time, the laser-excited energy is relaxed with a certain relaxation time, so the center 6 of the discharge region 5 cannot be moved upstream indefinitely compared to the center 8 of the rake light 7.

Therefore, from the data described below, the distance ΔX between both centers is set to satisfy O<ΔX≦[)−v/P8.

That is, FIG. 2 shows the relationship between the efficiency improvement of laser energy by reducing the ineffective region of laser excitation and the loss when laser excitation energy flows from the high frequency discharge region 5 to the region of the laser beam 7 by the laser gas flow 3. Ta.

FIG. 2 shows the relationship between the beam extraction position shift (distance between the two centers) ΔX and the laser output PL when the laser is emitted under the condition that v/P=1. In Fig. 2, the dashed line indicating the laser output of 1.0 represents the laser output value when a square laser beam is taken out at the high frequency power output P1, while the solid line indicates the circular aperture outside the discharge part. This is the result when a circular laser beam is oscillated by attaching (the size of the outer diameter of the laser beam). Here, the solid line A is the result when the high frequency power supply output is P1, and the solid line B is the result when the high frequency power supply output is P2 (<Pt).

That is, according to the solid line A in the figure, the laser output is maximum when ΔX is about 1/4D, but if ΔX is increased beyond this,
Although the ineffective region of laser excitation decreases roughly, the laser output PL decreases due to relaxation of laser excitation energy.

However, solid line B, where the high frequency power supply output is lower than solid line A,
In , ΔX at which the laser output P1 becomes maximum is larger than in the case of solid line A.

Therefore, from the results of solid line A and solid line B, it can be said that if the deviation ΔX of the beam extraction position is O<ΔX≦D, it is possible to increase the laser output more than when ΔX=O.

Furthermore, the faster the flow velocity V of the laser gas flow 3 is, the faster the laser excitation energy in the high-frequency discharge region 5 is carried to the laser beam 7, so that the excitation energy is less likely to be relaxed.

That is, the larger the flow velocity V is, the larger ΔX can be.

Roughly speaking, the higher the gas pressure P, the shorter the relaxation time, so it is necessary to reduce ΔX.

From the above conditions, by setting the distance ΔX between the center 6 of the high frequency discharge region 5 and the center 8 of the laser beam 7 to O<ΔX≦D−v/P, the laser oscillation output can be reduced by about 5 to 10%. can be raised.

*Other Embodiments* Note that the present invention is not limited to the embodiments described above, and the laser beam may be returned to the high frequency discharge region 5 many times as shown in FIG. In this case, the present invention can be applied by setting the distance between the laser beam 10a located at the most upstream side and the most upstream side of the high frequency discharge region 5 to be ΔX, and the laser output energy can be improved. Become.

[Effects of the Invention] As described above, according to the present invention, the center of the discharge area is
It is configured to be located upstream of the laser gas flow by ΔX compared to the center of the laser beam, and the distance between the two centers is ΔX (mm>), and the outer diameter of the laser beam is D (mm>,
The flow velocity of the laser gas flow is v (rn/s), and the gas pressure is P (
torr), the energy excited by the laser in the discharge region can be efficiently extracted to the outside as laser light energy by simply setting the condition to satisfy O<ΔX≦D−v/P. A laser device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a discharge section showing an embodiment of the laser device of the present invention, FIG. 2 is a diagram showing the relationship between beam extraction position shift ΔX and laser output, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a cross-sectional view showing an example of a conventional laser device. la, 1b... discharge electrode, 2a, 2b... dielectric,
3... Laser gas flow, 4... High frequency power supply, 5...
High frequency discharge region, 6... Center of high frequency discharge region, 7.
... Laser light, 8... Center of laser beam, 9... Ineffective region of laser excitation, 10 a, 10 b, 10
C.L/-sa light. Keyaki No. 1 Diagram

Claims (1)

[Scope of Claims] In a three-axis orthogonal laser device in which the direction of the discharge electric field, the direction of the laser gas flow, and the direction of the laser optical axis are orthogonal to each other, the center of the discharge region is located within the laser gas flow by ΔX compared to the center of the laser beam. The distance ΔX (mm) between the two centers is such that the outer diameter of the laser beam is D (mm), the flow velocity of the laser gas flow is V (m/s), and the gas pressure is When is P (torr), 0<ΔX≦D・V/
A laser device characterized in that it is set to satisfy P.