JPS6310598B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laser oscillation device with improved oscillation efficiency over a wide range of operating ranges.

In conventional solid-state laser oscillation devices, processing ability has been improved by increasing the oscillation output. For this reason, laser rods are becoming longer and thicker, and excitation lamps are being used that have approximately the same length of discharge portion to match this, and everything else is becoming larger. To give an example of such a device with a large output, as shown in FIG. 1, power is supplied from a laser power source 1 to two flash lamps 2 and 3, which are excitation lamps, to drive one laser rod 4. configured to excite. As shown in FIG. 2, such a device has two elliptical focusing surfaces 8, 9 each having two focal lines 5, 6, 5, 7, each of which shares one focal line 5. Multiple elliptical condensers 11 are used which are combined to face each other to form a multiple elliptical condensing surface 10. A laser rod 4 and a glass tube 12 surrounding it are disposed in one shared focal line 5, and the other It is constructed by arranging excitation lamps 2 and 3 on focal lines 6 and 7.

However, there is a relationship as shown in FIG. 3 between the laser oscillation efficiency of the above-mentioned device and the voltage applied to the excitation lamps 2 and 3. In this figure, the horizontal axis shows the excitation lamp 2,
FIG. 3 is a diagram showing the applied voltage V to No. 3 and the laser oscillation efficiency y on the vertical axis. If the excitation lamps 2 and 3 used have a discharge part with an inner diameter of 8 mm and a length of 150 mm, and are filled with krypton gas at approximately 1 atm, the applied voltage will be
It can be seen that the oscillation efficiency decreases significantly below 300V. When using the above lamps 2 and 3 in the above device, the oscillation efficiency of the laser output is good if the operating range of 300V or more is selected, but if the laser output is used at an even lower level, the oscillation efficiency suddenly decreases. I will do it. Furthermore, when a low voltage is applied to the excitation lamps 2 and 3, the light emitting portion within the discharge path is not uniform, and the excitation intensity within the cross section of the laser rod 4 is also disadvantageous. In order to avoid such drawbacks, it is possible to oscillate above a certain level without reducing the oscillation output, reduce the output by putting an aperture in the oscillator, or adjust the output by installing an external dimming means. is being carried out. In addition to the method described above, it is also conceivable to excite with only one excitation lamp 7. In this case, the excitation lamp 7 performs normal discharge, but as shown in _{FIG .} hardly contributes to excitation. In Figure 5, the horizontal axis shows the excitation lamp 6,
This is a diagram in which the laser oscillation output p from the above-mentioned device is plotted with the voltage V applied to 7 as the vertical axis, where curve a is the one when two excitation lamps 6 and 7 are emitted, and curve b is the one when the two excitation lamps 6 and 7 are emitted.
Curve c is a curve obtained when one excitation lamp 7 is emitted in this embodiment, which will be described later, and curve c is a curve obtained when one excitation lamp 7 is emitted in a conventional apparatus (FIG. 4). As shown in curve c, when one excitation lamp 7 is used, the output is less than half that of curve a. This is because there is a threshold value for starting laser oscillation. Furthermore, as mentioned above, the excitation light emitted to the regions θ ₁ and θ ₂ is not collected at the laser rod 4 and is wasted, but when irradiated from one direction in this way, the laser oscillation pattern is a skewed laser beam cross-sectional intensity distribution. This is an inconvenience that can easily occur.

The present invention has been made to eliminate the above-mentioned disadvantages, and by detachably providing a partial reflector within a multiple elliptical condenser, a laser oscillation device with high oscillation efficiency even in the case of low output oscillation. This is what you get.

The details of the present invention will be explained below with reference to an embodiment shown in FIG. The laser oscillation device of this embodiment has a first
It has almost the same configuration as the conventional example shown in the figure.
Since only the multiple elliptical condenser 11 is different, this part will be mainly explained.

A container body 15 made of an insulating material and having a rectangular parallelepiped shape
consists of a lid 16 and a main body 17, the main body 17 is provided with a recess 18, and by removing the lid 16, the multiple elliptical condenser 11 is inserted into the recess 18.
is now being accommodated. The multiple elliptical light condenser 11 has a rectangular parallelepiped shape, and has two elliptical light condensing surfaces 8 and 9 therein which share one focal line 5 as in the conventional example. The reflective surface 20, for example, as shown by the two-dot chain line, the portion where the elliptical condensing surface 8 enters the elliptical condensing surface 9 and the opposite portion thereof are removed to form a continuous multiple elliptical condensing surface 10. A laser rod 4 and a glass tube 12 are provided at one focal line 5, and excitation lamps (flash lamps) 2, 3 are provided at the other focal lines 6, 7, making this multiple elliptical condenser Cooling water is flowed into the chamber 11 to generate oscillation. A partial reflector 21 is further provided in the multiple elliptical condenser 11 in a detachable manner. This has a reflective surface 22 that is part of the elliptical condensing surface 9 that is the same as the cut out part 20, and the back surface 23 is appropriately formed in an arc shape and has a predetermined thickness so that it can be inserted and removed by surface contact. have. Although not shown, it is adapted to be detachably fixed to the end of the multiple elliptical condenser 11. It is used when causing the partial reflector 21 to oscillate at low output, for example when only the excitation lamp 3 is operated.
This reflective surface 22 complements the missing reflective surface of the elliptical condensing surface 9. When the excitation lamp 3 is operated in this state, the light directed to the regions θ ₁ and θ ₂ shown in FIG. That's what I do.

As detailed above, the laser oscillation device of the present invention is provided with a removable partial reflector to compensate for the cut off part of the multiple elliptical focusing surface, so when it is removed, all the excitation lamps are operated to generate high output. Even if the laser oscillation is performed efficiently and a partial reflector is installed, even if the excitation lamp is reduced, the elliptical focusing surface on the operating side is compensated for by the cut part, so all the light from the excitation lamp is The laser beam enters the laser rod and can efficiently oscillate a low-output laser with a uniform intensity distribution, making it possible to oscillate with high efficiency from high output to low output. In addition, since the partial reflector is in surface contact with the elliptical condensing surface, it will not rotate or shift when inserted, making it possible to easily configure a single elliptical condenser from a double elliptical condenser. .

In this embodiment, the case of a double elliptical light condenser has been described, but the present invention is not limited to this, and a case where three or more multiple elliptical light condensers are used may be used. It goes without saying that the partial reflective surface may be constructed of an elliptical condensing surface whose focal line is the same as that of the excised reflective surface, but in this case it is preferable that the partially reflective surface be larger than the excised reflective surface.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram of a conventional example and an embodiment of the present invention, Fig. 2 is a cross-sectional view of a conventional multiple elliptical condenser, and Fig. 3 is a relationship line between the applied voltage of the excitation lamp and the laser oscillation efficiency. Figure 4 is an explanatory diagram of the reflection state in a conventional multiple elliptical condenser, Figure 5 is a diagram of the relationship between the applied voltage of the excitation lamp and the oscillation output in the conventional example and the embodiment of the present invention, and Figure 6 is a diagram of the present invention. FIG. 1 is a sectional view of a main part of an embodiment of the invention. 2, 3...excitation lamp, 4...laser rod,
5... One focal line, 6, 7... The other focal line,
8, 9...Elliptical light condensing surface, 10...Multiple elliptical light condensing surface, 11...Multiple elliptical light condensing body, 20...Reflecting surface cut out, 21...Partial reflector.

Claims (1)

[Claims] 1 A continuous multiple ellipse is created by cutting out the reflective surface portion of a plurality of elliptical light condensers near the focal line of one of them and combining the cut elliptical light condensers so that the one focal line is shared. In a laser oscillation device having multiple elliptical condensers forming a condensing surface, a laser rod is placed at the position of one of the focal lines, and an excitation lamp is placed at each of the other focal lines,
The inner surface becomes the cutout reflective surface and has a thickness that allows it to be inserted into and removed from one of the cutout portions of the elliptical light collector by surface contact, and by insertion, at least a single ellipse light is focused in the multiple ellipse light collector. A laser oscillation device characterized by comprising a partial reflector that divides the body.