JPH0983045A - Solid state laser oscillator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make uniform the temperature distribution of a solid state laser rod, while enhancing the cooling efficiency, by cooling the solid state laser rod uniformly. SOLUTION: A water tank 2 is provided with a cooling water path 3, a port 4 for introducing a cooling water 7 into the cooling water path 3, and a discharge port 5. A solid state rod 8 is disposed in the cooling water path 3 through a rod holder 10 with the optical axis 9 directing a specified direction. The introduction port 4 and discharge port 5 are disposed oppositely while inclining at an angle 5 between the center lines 12, 13 and the optical axis 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state laser oscillator that optically pumps a solid-state laser rod by a pump lamp to oscillate the laser beam, and more particularly to improvement of a cooling water passage of the solid-state laser rod.

[0002]

2. Description of the Related Art Generally, as a structure of a cooling water passage of a solid-state laser rod of this type, there are structures shown in FIGS. 5 is a sectional view showing the cooling water channel, and FIG. 6 is a sectional view taken along line VI-VI in FIG. In these drawings, reference numeral 2 is a water tank having a cooling water passage 3 formed in a hollow shape, and cooling water 7 introduced into the cooling water passage 3 through an inlet 4 and discharged through an outlet 5 is provided. It is formed to pass through. 6 is a glass tube, 8 is a fixed laser rod having an optical axis 9, and 10 is a rod holder adhered and fixed to both ends of the fixed laser rod 8. Both ends of the rod holder 10 penetrate the water tank 2 and project from both ends of the water tank 2, and the projecting portions at both ends are held by a holding means (not shown).
The optical axis 9 of the fixed laser rod 8 is held so as to be directed in a predetermined direction. Reference numeral 11 is an O-ring that makes the water tank 2 have a liquid-tight structure.

Further, as another cooling water passage, Japanese Patent Laid-Open No.
There is one disclosed in 202077. What is disclosed here is that a solid laser rod is arranged in a glass pipe filled with cooling water, and a pair of rings having an inlet and an outlet are arranged at both ends of the glass pipe. The ring is installed close to the excitation lamp side so that the flow rate on the excitation lamp side is higher than the flow rate on the opposite side, thereby uniformly cooling the solid-state laser rod.

[0004]

However, in the former structure, the center line 1 between the inlet 4 and the outlet 5 for the cooling water is used.
Since the angle α formed by 2 and 13 and the optical axis 9 of the solid-state laser rod 8 is 90 °, the cooling water 7 introduced from the inlet 4 has a flow direction at a right angle at the inlet of the cooling water passage 3. Since it has to be changed, the flow path resistance here is large, and the flow direction of the cooling water 7 flowing into the cooling water path 3 must be changed at a right angle even at the inlet of the discharge port 3. Resistance also increases. Therefore, there is a problem that the flow rate of the cooling water 7 flowing from the inlet 4 into the cooling water passage 3 is reduced, and thus the cooling efficiency is reduced. Further, as shown in FIG. 6, so that the center line 12 of the inlet 4 and the center axis 14 of the solid-state laser rod 8 coincide with each other,
That is, the introduction port 4 is arranged so as to be located directly below the solid-state laser rod 8. Therefore, when the cooling water 7 introduced from the introduction port 4 reaches the bottom surface of the fixed laser rod 8, the cooling water passage 3b below the fixed laser rod 8 and the cooling water passage 3c on the front side of the fixed laser rod 8 and the rear side thereof. It branches in 3 directions with the cooling water passage 3d. Front side cooling water channel 3c
The cooling water 7 flowing into the cooling water passage 3d on the rear side and the cooling water passage 3d on the back side interfere with each other above the fixed laser rod 8, so that the flowing speed decreases, and the amount of inflow into the cooling water passage 3b above decreases, thereby cooling the upper portion. The flow rate in the cooling water passage 3b below the water passage 3a increases. Therefore, there is also a problem that the solid laser rod 8 is not uniformly cooled above and below. Further, in the latter structure, it is difficult to control the cooling water above and below the fixed laser rod, and it is not applicable to the structure in which the excitation lamp is arranged above and below the fixed laser rod.

Therefore, the present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to uniformly cool the solid-state laser rod and to make the temperature distribution of the solid-state laser rod uniform. At the same time, another object is to provide a fixed laser oscillation device with improved cooling efficiency.

[0006]

In order to achieve this object, a fixed laser oscillator according to the present invention is provided with a solid laser rod for optically oscillating a laser by exciting a pump lamp in a cooling water channel. In a solid-state laser oscillating device having an inlet for introducing cooling water and an outlet for discharging cooling water in a water channel, the center lines of the inlet and the outlet are displaced from the center line of the laser rod and positioned. The inlet and the outlet are tilted in a direction facing each other with respect to the optical axis of the laser rod. Therefore, the cooling water introduced from the introduction port does not interfere with the fixed laser rod on the opposite side of the introduction port, and the flow resistance of the cooling water introduced from the introduction port and the cooling discharged to the discharge port are eliminated. The flow path resistance of water is reduced.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a sectional view of a fixed laser oscillator according to the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG. In these figures, the same or equivalent members described in the above-described prior art shown in FIGS. 5 and 6 are designated by the same reference numerals, and detailed description thereof will be omitted. The feature of the present invention resides in that the inlet port 4 and the outlet port 5 have respective center lines 12 and 13 and the optical axis 9 of the fixed laser rod 8 at an angle α of about 60 °. And the discharge port 5 are inclined in the directions facing each other.

By doing so, the cooling water 7 introduced from the inlet 4 changes its flow direction gently in the cooling water passage 3, so that the flow passage resistance here becomes small. Moreover, since the cooling water 7 introduced into the cooling water passage 3 can gently change its flow direction even when introduced into the discharge port 5, the flow path resistance here is also small. Therefore, the flow rate of the cooling water 7 introduced from the introduction port 4 and flowing into the cooling water passage 3 does not decrease, and therefore, the cooling efficiency of the fixed laser rod 8 by the cooling water 7 is improved.

Another feature of the present invention is that
As shown in FIG. 2, the center line 12 of the introduction port 4 is positioned with a distance δ displaced from the center line 14 of the fixed laser rod 8, and although not shown in the figure, the discharge port 5 also includes the discharge port 5 of the discharge port 5. The center line is located at a position displaced by a distance δ from the center line 13 of the fixed laser rod 8.

By doing so, the cooling water 7 introduced from the inlet 4 enters the cooling water channel 3c on the front side from the tangential direction, so that when the bottom surface of the fixed laser rod 8 is reached, most of the cooling water 7 is in front. Flows into the side cooling water passage 3c.
Therefore, the cooling water 7 does not interfere with each other in the upper cooling water passage 3a, and the upper cooling water passage 3 smoothly flows.
Since it flows into a, the cooling water 7 flows evenly into the upper cooling water passage 3a and the lower cooling water passage 3b. Therefore, the upper and lower surfaces of the fixed laser rod 8 are uniformly cooled, and the temperature distribution of the solid-state laser rod 8 is made uniform. In this way, the cooling water 7 guided from the cooling water passage 3c on the front side to the cooling water passage 3a on the upper side is inclined in the direction in which the introduction port 4 and the discharge port 5 face each other as described above. As shown in FIG. 1, it flows spirally around the fixed laser rod 8 and is discharged from the discharge port 5.

3 and 4 show a second embodiment of the present invention, FIG. 3 is a sectional view, and FIG. 4 is a sectional view taken along line IV-IV in FIG. The second embodiment is characterized in that an inlet 15 and an outlet 16 are also provided on the upper side of the water tank 2 so as to face the inlet 4 and the outlet 5. These inlets 1
Similarly to the inlet 4 and the outlet 5, the outlet 4 and the outlet 15 are formed such that their center lines 17 and 18 are inclined with respect to the optical axis 9 so as to face each other.

Further, as shown in FIG. 4, the introduction port 15 is positioned on the opposite side of the introduction port 4 with the central axis 14 of the fixed laser rod 8 interposed therebetween, with a center line 17 displaced by a distance δ. Similarly, although not shown, the discharge port 16 is also positioned with the center line 18 displaced by a distance δ on the opposite side of the discharge port 5 with the central axis 14 of the fixed laser rod 8 interposed therebetween.

With such a configuration, the cooling water 7 introduced from both inlets 4 and 15 has the center lines 12 and 15 of both inlets 4 and 15 on the central axis 14 of the fixed laser rod 8. Since they are positioned with the distance δ displaced to the opposite side with respect to each other, they enter the cooling water channel 3 from the tangential direction, so that the cooling water 7 does not interfere with each other as shown in FIG. Flow to rotate. Therefore, the same amount of cooling water is supplied to the upper and lower sides of the fixed laser rod 8 as in the above-described first embodiment, and the amount thereof is double that in the first embodiment. The cooling rate for cooling the fixed laser rod 8 is 2
Double.

[0014]

As described above, according to the present invention, the center lines of the inlet for introducing the cooling water for cooling the solid laser rod and the outlet for discharging the cooling water are displaced from the center line of the solid laser rod. By being positioned,
The cooling water introduced from the introduction port is smoothly introduced into the cooling water channel on the opposite side of the introduction port with the fixed laser rod interposed therebetween, so that the fixed laser rod is uniformly cooled and the temperature distribution of the solid laser rod is uniform. Be promoted. In addition, since the inlet and the outlet are inclined in the direction facing each other with respect to the optical axis of the fixed laser rod, the flow resistance of the cooling water introduced from the inlet and the cooling water discharged to the outlet is Does not increase, and therefore the flow rate of the cooling water does not decrease, thus improving the cooling efficiency.

Further, according to the present invention, a pair of inlets and outlets are provided so as to face each other with the solid-state laser rod sandwiched therebetween, and the inlets and outlets are provided with the optical axis of the laser rod. With respect to each other, the inlets and the outlets are positioned such that their center lines are displaced in opposite directions with the center line of the laser rod interposed therebetween.
Since the cooling water introduced from the pair of inlets flows so as to rotate around the solid laser rod without interfering with each other, the fixed laser rod is uniformly cooled, and the flow rate of the cooling water is sufficiently increased. Cooling is performed.

[Brief description of drawings]

FIG. 1 is a sectional view of a fixed laser oscillator according to the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view showing a second embodiment of a fixed laser oscillator according to the present invention.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a sectional view of a conventional fixed laser oscillator.

6 is a sectional view taken along line VI-VI in FIG.

[Explanation of Codes] 2 ... Water Tank, 3 ... Cooling Water Channel, 4, 15 ... Inlet, 5, 16
... discharge port, 7 ... cooling water, 8 ... fixed laser rod, 9 ... optical axis, 10 ... rod holder, 12, 13, 17, 18 ... center line.

Claims (2)

[Claims] 1. A solid body comprising a solid-state laser rod, which is optically excited by an excitation lamp to oscillate a laser, in a cooling water channel, and has an inlet for introducing cooling water and an outlet for discharging cooling water in the cooling water channel. In the laser oscillation device, the center line of the introduction port and the discharge port is displaced from the center line of the laser rod and positioned, and the introduction port and the discharge port are
A solid-state laser oscillating device, wherein the solid-state laser oscillating device is inclined with respect to the optical axis of the laser rod. 2. A solid body, in which a solid-state laser rod that is optically excited by a pump lamp to oscillate a laser is disposed in a cooling water passage, and an inlet for introducing cooling water and an outlet for discharging the cooling water are provided in the cooling water passage. In the laser oscillating device, the pair of inlets and outlets are provided so as to face each other with the solid-state laser rod interposed therebetween, and these inlets and outlets are mutually centered so that the center line of the laser rod is A solid-state laser oscillating device, characterized in that it is positioned by being displaced in opposite directions with a center line interposed therebetween, and that the inlet and the outlet are inclined in directions facing each other with respect to the optical axis of the laser rod.