JPH0729863U - Metal vapor laser equipment - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] A metal vapor laser device that can apply an optimum transverse magnetic field and can reduce the change in the optical axis of the laser mirror due to the effect of thermal expansion due to heat generation during laser operation. I will provide a. [Arrangement] Mirror holding means 20 containing a laser mirror
And a rod 30 for connecting a pair of mirror holding means to form a laser resonator, and a metal vapor laser tube 40 having a laser thin tube 41 inside and a metal and a carrier gas sealed therein.
In the metal vapor laser device consisting of, a magnet 70 is held in the space between the metal vapor laser tube and the rod so as to give a transverse magnetic field to the metal vapor laser tube, and a moving means in the direction of the transverse magnetic field is provided. In addition, it has a magnet holding flat plate 60 for blocking light and heat radiation given to the rod from the metal vapor laser tube.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a metal vapor laser device.

[0002]

[Prior art]

 The metal vapor laser device encloses a metal and a carrier gas in a laser tube and uses the vapor of the metal to cause laser oscillation. Currently, the metal vapor laser device that has been put into practical use is a so-called positive column type in which laser oscillation is performed using the positive column part of the discharge. Specifically, helium is used as the carrier gas and cadmium is used as the metal. The following positive column type He-Cd laser device is known. This He-Cd laser device can continuously oscillate ultraviolet light having a wavelength of 325 nm and visible light having a short wavelength region of 422 nm. Therefore, for example, as a light source for exposing a photoresist, a light source for photocuring when creating a model of a human body structure or bone using data obtained by CT, a light source for fluorescence analysis, etc. It is expected to be used in various fields.

FIG. 3 is an explanatory diagram of a main part of a conventional positive column type metal vapor laser device. Reference numeral 1 is one mirror holder containing a laser mirror that constitutes a laser resonator. This mirror holder 1 is connected to another mirror holder (not shown) of the other set by three or four rods 2 having a small coefficient of thermal expansion, such as Invar, to form a laser resonator. 3 is a metal vapor laser tube in which a metal and a carrier gas are sealed, 4 is a laser thin tube provided inside the metal vapor laser tube 3, and 5 is for the metal vapor laser tube 3 and the laser thin tube 4. The magnet for applying a substantially uniform transverse magnetic field in a direction substantially perpendicular to the laser light emitting direction. 6 is a cathode part. The magnetic field is applied here because the application of the magnetic field is effective in increasing the laser output and reducing noise, as disclosed in, for example, Japanese Patent Publication No. 47-3513 and Japanese Patent Application Laid-Open No. 63-255981.

[0004]

[Problems to be solved by the device]

 In the conventional commercially available metal vapor laser device as described above, the magnet 5 is directly bonded to the metal vapor laser tube 3 or attached to the rod 2. Generally, in the metal vapor laser device, parameters such as the diameter and the length of the metal vapor laser tube 3 and the laser thin tube 4 and the gas conditions to be enclosed vary according to the desired performance such as laser light output. On the other hand, the applied magnetic field has individual optimum values according to these various parameters. Therefore, as described above, when the magnet 5 is installed, the magnetic field is fixed, so that it is necessary to prepare a magnet 5 suitable for each time the above parameters are changed. Therefore, the number of parts increases and the cost increases. Further, since the outer shapes of the rod 2 and the metal vapor laser tube 3 are usually cylindrical, it takes time and effort to install the magnet 5 so that the transverse magnetic field can be applied substantially uniformly in a predetermined direction.

By the way, the metal vapor laser device generates heat from the inside of the metal vapor laser tube 3 during its operation, and a high temperature is generated especially on the cathode side of the discharge electrode. Therefore, the optical axis of the laser mirror changes due to the difference in thermal expansion caused by the temperature gradient accompanying the radiant heat. That is, since the laser output changes, there is a problem in that a service interruption time is required for readjustment of the optical axis. As described above, the pair of mirror holders 1 containing the mirrors forming the laser resonator are connected by the rod 2 having a small coefficient of thermal expansion in order to reduce the influence of such thermal expansion. The metal vapor laser tube 3 is cooled by a cooling means such as a fan (not shown) in FIG.

However, the influence of thermal expansion cannot be ignored even if the laser resonator is constructed in this way or the metal vapor laser tube 3 is cooled. This is because the use of Invar or the like for the rod 2 does not mean that the rod 2 does not completely expand. When the inventor investigated the fluctuation of the laser light output using a He—Cd laser device, which is a typical example of a metal vapor laser device on the market, it was confirmed that the laser light output fluctuated up to ± 20%. The fluctuation value is obtained based on the average value of the maximum value and the minimum value of the laser output in any specific time zone.

Therefore, the present invention has been made in view of such circumstances, and an object thereof is to apply an optimum transverse magnetic field even if a design parameter of a metal vapor laser device changes in order to obtain desired performance. The magnets 5 can be made of different types of magnets, and the magnets 5 can be installed so that the transverse magnetic field can be applied in a predetermined direction almost uniformly. An object of the present invention is to provide a metal vapor laser device capable of reducing the change in the optical axis of the laser mirror due to the influence of thermal expansion.

[0008]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention provides a mirror holding means containing a laser mirror, a rod for connecting the mirror holding means to form a laser resonator, a laser capillary tube inside, and a metal and a carrier gas. In a space between the metal vapor laser tube and the rod, a magnet is held so as to give a transverse magnetic field to the metal vapor laser tube, and a transverse magnetic field A magnet holding plate which has means for moving in this direction and blocks the light and radiant heat given to the rod from the metal vapor laser tube is installed.

Further, it is desirable that the holding flat plate is made of a ferromagnetic material such as SS41.

[0010]

[Action]

 Since the magnet holding plate installed in the space between the metal vapor laser tube and the rod holds the magnet on the plate, a transverse magnetic field is easily applied in a predetermined direction. Further, since the magnet holding plate has a moving means in the direction of the transverse magnetic field, the distance between the magnets held facing each other can be adjusted so as to give the transverse magnetic field. Therefore, even if the design parameters of the metal vapor laser device are changed to obtain the desired performance, it is possible to apply the optimum transverse magnetic field with one type of magnet. Furthermore, since the magnet holding plate is installed so as to block the light and radiant heat given to the rod from the metal vapor laser tube, thermal expansion of the laser mirror due to heat generation during laser operation causes The change in the optical axis is reduced.

If the holding plate is made of a ferromagnetic material, a transverse magnetic field can be applied substantially uniformly in a predetermined direction.

[0012]

【Example】

 The present invention will be described in detail below based on the embodiments shown in the drawings. FIG. 1 is a schematic cross-sectional view of a metal vapor laser device according to an embodiment of the present invention as seen from the optical axis direction. Reference numeral 10 is a housing of the laser device, and 20 is a mirror holder containing a laser mirror forming a laser resonator. The mirror holder 20 is connected to another mirror holder (not shown) by three or four rods 30 having a small thermal expansion coefficient such as Invar to form a laser resonator. Reference numeral 40 is a metal vapor laser tube in which a metal and a carrier gas are sealed, and 41 is a laser thin tube provided inside the metal vapor laser tube 40. Reference numeral 50 is an air-cooling fan for cooling the metal vapor laser tube 40 during laser operation. Reference numeral 60 denotes a magnet holding flat plate made of SS41, which is installed so that the magnet 70 faces each other with the metal vapor laser tube interposed therebetween. The length of the magnet holding plate 60 in the longitudinal direction is equal to the length of the metal vapor laser tube 40.

FIG. 2 is an explanatory diagram of a lower portion of the magnet holding flat plate 60. As shown in FIG. 2, the lower portion 62 of the magnet holding flat plate 60 is bent, and a plurality of elongated holes 63 are provided on the surface in contact with the bottom surface of the laser device housing 10. The elongated hole 63 is located on the mounting hole 11 provided on the bottom surface of the laser housing 10 and is mounted by the screw 80. The upper portion 61 of the magnet holding plate 60 is bent so as to shield the rod 30 from the metal vapor laser tube 40.

Since the magnet 70 is held by the magnet holding flat plate 60 which is a flat plate, not by the rod 30 or the metal vapor laser tube 40 which is usually a columnar shape, the horizontal axis of the magnetic field can be easily carried out in a predetermined direction. Can be applied to. Moreover, since the magnet holding plate 60 is made of SS41 which is a ferromagnetic material, it is possible to apply a transverse magnetic field to the metal vapor laser tube 40 substantially uniformly.

In the magnet holding plate 60, the relative position of the elongated hole 63 provided in the lower portion 62 and the mounting screw hole 11 provided in the bottom surface of the laser housing 10 is adjusted to move the magnet holding flat plate 60. Adjust the distance d. That is, since the transverse magnetic field applied to the metal vapor laser tube 40 can be arbitrarily adjusted, the optimum transverse magnetic field can be applied even if the design parameter of the metal vapor laser device changes to obtain desired performance. Therefore, the optimum transverse magnetic field can be applied to the metal vapor laser device of various performances with only one type of magnet 70, so that the number of parts can be reduced and the cost can be reduced.

The length of the magnet holding plate 60 in the longitudinal direction is equal to the length of the metal vapor laser tube 40 and is installed in the space between the metal vapor laser tube 40 and the rod 30. The upper portion 61 is bent so as to shield the rod 30 from the metal vapor laser tube 40. Therefore, the light or radiant heat given from the metal vapor laser tube 40 to the rod 30 is blocked or reduced, so that the optical axis of the laser mirror changes due to thermal expansion of the rod 30 due to the influence of heat generation during laser operation. Can be reduced, and the down time for readjustment of the optical axis can be reduced.

The inventor modified a He—Cd laser device, which is a typical example of the above-mentioned commercially available metal vapor laser device, by modifying the laser light output as in this embodiment, and investigated the fluctuation of the laser light output. It was confirmed that was reduced from a maximum of ± 20% to a maximum of ± 10% or less. The fluctuation value is obtained based on the average value of the maximum value and the minimum value of the laser output in any specific time zone.

It should be noted that FIG. 1 shows only one embodiment of the present invention. In this embodiment, the position adjustment of the magnet holding flat plate 60, that is, the distance d between the magnets is adjusted by the long hole 63 provided in the lower portion 62 of the magnet holding flat plate 60 and the mounting screw provided on the bottom surface of the laser housing 10. Although the relative position of the hole 11 is adjusted, a set of magnet holding flat plates 60 may be installed on a linear mechanism such as a linear guide to adjust the position.

Further, the length of the magnet holding plate 60 in the longitudinal direction does not necessarily have to be equal to the length of the metal vapor laser tube 40, and may be long depending on the degree of fluctuation of the laser light output due to thermal expansion of the rod 30. May be short, and further, it is not always necessary to be continuous in the longitudinal direction.

[0020]

[Effect of device]

 As explained above, the metal vapor laser device of the present invention holds the magnet in the space between the metal vapor laser tube and the rod so as to give a transverse magnetic field to the metal vapor laser tube, and To the metal vapor laser tube in a predetermined direction with a transverse magnetic field in a predetermined direction, since it has a magnet holding flat plate for blocking light and radiant heat given to the rod from the metal vapor laser tube. Can be applied. Further, since the magnet holding plate has a moving means in the direction of the transverse magnetic field, the distance between the magnets held facing each other can be adjusted so as to give the transverse magnetic field. Therefore, even if the design parameters of the metal vapor laser device change to obtain the desired performance, the optimum transverse magnetic field can be applied by one type of magnet. Furthermore, since the magnet holding plate is installed so as to block the light and radiant heat given from the metal vapor laser tube to the rod, the optical axis of the laser mirror is affected by the thermal expansion due to the heat generated during laser operation. Can be reduced. In particular, if the magnet holding plate is made of a ferromagnetic material, it is possible to apply a transverse magnetic field almost uniformly in a predetermined direction.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a metal vapor laser device according to an embodiment of the present invention viewed from the optical axis direction.

FIG. 2 is an explanatory diagram of a lower portion of a magnet holding flat plate 60.

FIG. 3 is an explanatory diagram of a main part of a conventional positive column type metal vapor laser device.

[Simple explanation of symbols]

 10 Laser Device Housing 11 Mounting Hole 20 Mirror Holder 30 Rod 40 Metal Vapor Laser Tube 41 Laser Capillary Tube 50 Air-cooling Fan 60 Magnet Holding Plate 70 Magnet 80 Screw d Magnet Distance 1 Mirror Holder 2 Rod 3 Metal Vapor Laser Tube 4 Laser Capillary Tube 5 Magnet 6 Cathode part

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hironari Haneda 1194 Sado, Bessho-cho, Himeji-shi, Hyogo Ushio Electric Co., Ltd.

Claims (2)

[Scope of utility model registration request] 1. A mirror holding means containing a laser mirror, a rod for connecting a set of mirror holding means to form a laser resonator, and a laser thin tube are provided inside, and a metal and a carrier gas are enclosed. In a metal vapor laser device comprising a metal vapor laser tube and a metal vapor laser tube, a magnet is held in a space between the metal vapor laser tube and a rod so as to give a transverse magnetic field to the metal vapor laser tube, A metal vapor laser device having a moving means and a magnet holding flat plate for blocking light or radiant heat given to the rod from the metal vapor laser tube. 2. The metal vapor laser device according to claim 1, wherein the magnet holding plate is made of a ferromagnetic material.