JP2007067025A - Laser rod cooling and holding structure and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser rod cooling and holding structure capable of effectively dissipating heat generated in a laser rod in a miniature high output laser oscillator. <P>SOLUTION: The cooling and holding structure includes a cooling and holding sleeve 1 composed of an excitation light incidence window 4 disposed around a laser rod 2 for making excitation light from a semiconductor laser element enter, and of a recess 8 for holding the laser rod 2 in which a filler 3 is filled for obtaining thermal coupling with the laser rod 2; and the filler 3 filled in the recess 8 of the sleeve 1. A filler 7 before melting is filled in a filler storage 9 under ordinary temperature and atmospheric pressure such that air in the recess 8 is released to the atmosphere, and the whole of the cooling and holding structure including the filler storage 9 is heated to a temperature where the filler 7 before melting is melted in a vacuum state. Further, the whole of the cooling and holding structure is returned to ordinary pressure while heating the filler 7 before melting to securely and uniformly fill the filler 3 in a gap between the laser rod 2 and the sleeve 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a laser rod cooling and holding structure for a solid-state laser oscillation device, and in particular, a laser oscillation device using a semiconductor laser element that can be used for a small-sized, high-output, space-equipment-equipped device that requires environmental resistance. The present invention relates to a laser rod cooling and holding structure and a manufacturing method thereof.

  When the excitation light enters from the periphery of the laser rod, the laser rod for the solid-state laser oscillation device absorbs the excitation light and generates heat therein. As a result of the thermal expansion of the laser rod due to an internal temperature rise, the refractive index changes greatly, the output is lowered, and the laser rod may even be damaged by thermal stress. Therefore, it is necessary to cool the laser rod, and various laser rod cooling and holding structures have been studied.

  For example, Patent Documents 1 to 3 all relate to the cooling and holding structure of the laser rod, and by filling the gap between the laser rod and the holding sleeve for cooling with a highly thermally conductive fluid or an adhesive, Aims for efficient heat dissipation.

JP-A-8-125250 JP-A-7-335554 JP-A-6-283788

  However, when using a small, high-power, small-diameter laser rod, the excitation light incident windows provided on the sleeve for holding and cooling the laser rod are connected to each other, and the area for holding the laser rod is very large. Get smaller. Therefore, even if it is difficult to realize the conventional cooling and holding structure, or even if the conventional cooling and holding structure can be applied, the amount of heat radiation decreases as the holding area decreases.

  Moreover, even if the adhesive has high thermal conductivity, the thermal conductivity is reduced by about three orders of magnitude compared to metal. For this reason, the plan of pouring the molten metal instead of an adhesive agent etc. can be considered. However, there is almost no gap between the laser rod and the cooling sleeve, and it has been difficult to completely fill the gap with metal in a state where heat conduction is good.

  Accordingly, the present invention has been made in view of the above-described conventional technique, and in order to prevent a decrease in heat dissipation efficiency associated with downsizing and weight reduction of a laser oscillation part or the like of a semiconductor solid laser oscillator, a laser rod and a cooling sleeve An object of the present invention is to provide a laser rod cooling and holding structure and a manufacturing method capable of efficiently dissipating heat by utilizing a small contact area between them.

  In order to achieve the above object, the present invention provides a laser rod cooling and holding structure, an excitation light incident window that is disposed around a laser rod and that allows excitation light from a semiconductor laser element to enter, and the laser rod includes: A cooling holding sleeve comprising a recess filled with a filling for obtaining thermal coupling with the laser rod, and a filling filled in the depression of the cooling holding sleeve. .

  According to the present invention, since the filling for obtaining thermal coupling is filled between the cooling holding sleeve and the laser rod via the recess, the small contact area between the laser rod and the cooling sleeve is utilized. Therefore, it is possible to efficiently dissipate heat, uniform temperature distribution during heat generation of the laser rod, and stable laser light output can be obtained.

  In the laser rod cooling and holding structure, in order to inject the filler into the recess, the filler holding portion communicating with the recess can be provided in the cooling and holding sleeve. Moreover, the said filler can be made into a metal or an adhesive agent. Furthermore, the filling can be indium. By using indium having a low melting point and good thermal conductivity, the laser rod can be efficiently cooled and held, and this cooling and holding structure can be easily realized.

  Further, the present invention is arranged around the laser rod, for holding an excitation light incident window for allowing excitation light from a semiconductor laser element to enter, and for holding the laser rod and obtaining thermal coupling with the laser rod. In a manufacturing method of a laser rod cooling and holding structure comprising a cooling holding sleeve provided with a recess filled with a filler and a filling filled in the recess of the cooling holding sleeve, at normal temperature and atmospheric pressure, The step of filling the filling material into the filling material reservoir that communicates with the recess so that the air inside the concave portion is released to the atmosphere, and the entire laser rod cooling and holding structure including the filling material reservoir is vacuumed Heating to a temperature at which the filler melts in a state, and returning the entire laser rod cooling and holding structure including the filler reservoir to normal pressure while heating the filler. Characterized in that it obtain.

  According to this manufacturing method, it is possible to reliably and uniformly fill the gap between the laser rod and the holding cooling sleeve, thereby realizing a cooling holding structure capable of cooling and holding the laser rod efficiently. Can do.

  As described above, according to the present invention, a small contact area between the laser rod and the cooling sleeve is utilized in order to prevent a decrease in heat dissipation efficiency due to the reduction in size and weight of the laser oscillation part of the semiconductor solid laser oscillator. In addition, it is possible to efficiently dissipate heat.

  FIG. 1 shows an embodiment of a laser rod cooling and holding structure according to the present invention. This cooling and holding structure is a cooling and holding sleeve (hereinafter abbreviated as “sleeve”) made of a material having high thermal conductivity. 1, a laser rod 2 inserted into the sleeve 1, and a filler 3, which is a metal having a high thermal conductivity and a low melting point, filling the gap between them.

  The sleeve 1 includes an excitation light incident window 4, a filler inlet 5, and a mounting flange 10. Further, the sleeve 1 is provided with a hole 11 into which the laser rod 2 can be inserted in the axial direction at the time of manufacture, and laser light is emitted from the hole 11. Further, the hole 11 has a hole diameter at which a gap with the laser rod 2 is minimized in a portion where the laser rod 2 is held.

  As shown in FIG. 1 (d), a plurality of excitation light incident windows 4 are arranged around the circumference of the laser rod 2 so as to allow excitation light to enter, as shown in FIG. 1 (b). 2 is partially exposed. As a result, the sleeve 1 can come into contact with the laser rod 2 in a region other than the excitation light incident window 4. In the remaining region, the heat generated by the laser rod 2 can be radiated to the sleeve 1 by heat conduction.

  As described above, there is a slight gap between the sleeve 1 and the laser rod 2, and there is no thermal coupling. Therefore, the gap is filled with the filler 3 so that the most efficient thermal coupling is obtained in this region. The sleeve 1 is provided with a filler inlet 5, a recess 8, and a filler reservoir 9 so that the filler 3 can be reliably filled. Moreover, the filling material storage part 9 shall have a larger volume than the recessed part 8 so that it can be reliably filled with the filling material 3 in the manufacturing method mentioned later.

  By completely filling the gap between the laser rod 2 and the sleeve 1 with a filler having high thermal conductivity, the heat from the laser rod 2 is conducted to the sleeve 1 and further to the mounting flange 10, and from the mounting flange 10. Heat can be radiated efficiently. In addition, it is preferable to use indium as the filler 3 having a low melting point and good thermal conductivity.

  Next, a manufacturing method of the laser rod cooling and holding structure having the above configuration will be described.

  After fixing the laser rod 2 to the sleeve 1, the pre-melting filler 7 is melted and poured from the filler inlet 5. However, if the pre-melting filler 7 is simply melted and poured from the filler inlet 5, as shown in FIG. 2, the filler 3 cannot be poured into the required portion (recessed portion 8) due to the influence of surface tension. . Therefore, after the pre-melting filling 7 is melted in a vacuum state, the filling 3 is injected into the recess 8 by returning to normal pressure and using the external pressure. The procedure will be described in detail with reference to FIG.

(1) The concave portion 8 is closed with an adhesive 6 or the like so that air does not enter and exit from other than the filler inlet 5 (see FIG. 4A).
(2) Packing the pre-melting filler 7 into the filler inlet 5 at atmospheric pressure and normal temperature. At this time, the pre-melting filler 7 is packed into a thin thread or particle form so that the air in the recess 8 can escape.
(3) Put the inside in an oven that can be evacuated and vacuum at room temperature.
(4) After the inside of the oven is evacuated, the temperature is equal to or higher than the melting point of the pre-melting packing 7. The melted pre-melting filler 7 is stored in the filler reservoir 9 (see FIG. 4B).
(5) The inside of the oven is returned to normal pressure while the temperature is raised. As a result, the melted pre-melting filler 7 flows into the concave portion 8 by the external pressure applied through the filler inlet 5 and the filler reservoir 9 (see FIG. 4C).

  In the above embodiment, the filler 3 can be made of an adhesive having a high thermal conductivity instead of a metal such as indium. Filling the adhesive is listed in the prior art, but by using the above manufacturing method, it is possible to reliably fill the concave portion 3 with the adhesive. Further, the filling reservoir 9 may be constituted by other parts instead of being provided directly on the sleeve 1 and removed after manufacture.

It is a figure which shows one Embodiment of the laser rod cooling holding structure concerning this invention, (a) is a perspective view, (b) is a longitudinal cross-sectional view, (c) is a cross-sectional view, (d) is (b) It is an AA line sectional view of). It is sectional drawing which shows the filler storage part vicinity in the case of not being based on the manufacturing method of the laser rod cooling / holding structure concerning this invention. It is sectional drawing for demonstrating the manufacturing method of the laser rod cooling holding structure concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sleeve 2 Laser rod 3 Filling material 4 Excitation light entrance window 5 Filling material inlet 6 Sealing adhesive 7 Filling material before melting 8 Recess 9 Filling material reservoir 10 Mounting flange 11 Hole

Claims (5)

An excitation light incident window for allowing excitation light from a semiconductor laser element to enter and a filler for holding the laser rod and obtaining thermal coupling with the laser rod are filled around the laser rod. A cooling holding sleeve comprising a recess,
A laser rod cooling and holding structure, comprising: a filling material that fills the concave portion of the cooling and holding sleeve.   2. The laser rod cooling and holding structure according to claim 1, wherein the cooling and holding sleeve includes a filling material reservoir that communicates with the concave portion in order to inject the filling material into the concave portion.   The laser rod cooling and holding structure according to claim 1, wherein the filler is a metal or an adhesive.   The laser rod cooling and holding structure according to claim 3, wherein the filler is indium. An excitation light incident window that is disposed around the laser rod and allows the excitation light from the semiconductor laser element to enter, and a filler for holding the laser rod and obtaining thermal coupling with the laser rod are filled. In a manufacturing method of a laser rod cooling and holding structure comprising: a cooling holding sleeve provided with a recessed portion; and a filler filled in the recessed portion of the cooling holding sleeve.
Filling the filling material into the filling material reservoir connected to the recess so that the air inside the recess is released into the atmosphere at room temperature and atmospheric pressure;
Heating the entire laser rod cooling and holding structure including the filling reservoir to a temperature at which the filling melts in a vacuum state;
And a step of returning the entire laser rod cooling and holding structure including the filling reservoir to normal pressure while heating the filling, and manufacturing the laser rod cooling and holding structure.

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