JP2016157829A - Laser beam damper and laser device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser beam damper capable of achieving a long lifetime, reducing return light by confining a laser beam and a laser device including the same.SOLUTION: The laser beam damper for blocking a laser beam includes a beam incident port 11 and a heat conduction member 1 having an annular part 13 formed in an annular shape. At an outer circumferential surface of the annular part 13, a light reflection film for reflecting light is formed. At an inner circumferential surface of the annular part 13, a light absorbing film for absorbing light is formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laser beam damper that absorbs a blocked laser beam when the laser beam is blocked, and a laser apparatus using the same.

  The laser beam damper has a function of blocking laser light and is used for ensuring the safety of the laser device and controlling the light. For example, in a wavelength converter for obtaining laser light having a desired wavelength, a laser beam damper is used for processing infrared light that has not been wavelength-converted after passing through a wavelength conversion crystal.

  FIG. 6 is a block diagram showing an example of a conventional laser beam damper. In this laser beam damper, a beam absorbing portion 5 using a metal material excellent in light absorption and thermal conductivity is integrated with a heat sink 6. The laser beam is converted into heat through the metal material and cooled by the heat sink 6. The beam absorption unit 5 is arranged to be inclined at a predetermined angle with respect to the laser optical axis, and absorbs the beam with a larger area.

  Since this laser beam damper converts laser light into heat and emits it, if the incident high-power laser light continues to be irradiated at the same position, the laser light absorbing member (beam absorbing portion 5) is locally very hot. become. For this reason, by repeatedly using the laser beam damper, the laser light absorbing member is remarkably deteriorated, and the performance as a damper is lowered. Therefore, in order to extend the life of the damper, it is necessary to reduce the damage to the laser light absorbing member by dispersing the beam when the beam is incident.

  For example, Patent Documents 1 to 4 are known as solutions for solving the problems of the laser beam damper. In Patent Document 1, the lens diameter of a target laser beam is widened by a lens, and consumption of the laser light absorbing member is suppressed. In Patent Document 4, a plurality of laser beam branching means are used to divide a laser beam into a plurality of parts, thereby suppressing the consumption of the laser beam absorbing member.

Japanese Unexamined Patent Publication No. 7-24591 JP-A-7-27903 Japanese Patent Laid-Open No. 10-326931 JP 2001-317995 A JP 2012-243850 A

  However, Patent Documents 1 and 4 require an optical system such as a mirror and a lens, and Patent Documents 2 and 3 also have a complicated structure.

  In the wavelength conversion device, when the target infrared light reenters the wavelength conversion unit or the like as return light, the temperature of the crystal rises and the wavelength conversion efficiency decreases. In the conventional technique shown in FIG. 6, the beam is not completely absorbed by the damper, and light may be emitted from the damper by being repeatedly reflected, and may become return light. The return light not only causes performance degradation in the wavelength converter, but also often causes defects such as a decrease in detector sensitivity in other laser devices. Such a problem is described in Patent Document 5. For this reason, it is necessary to effectively confine the used beam in the damper so that no return light is generated.

  An object of the present invention is to provide a laser beam damper capable of realizing a long lifetime and confining a laser beam to reduce return light, and a laser apparatus using the same.

  In order to solve the above problems, the present invention is a laser beam damper for blocking a laser beam, and includes a heat conduction member having a beam incident port and an annular portion formed in an annular shape, A light reflecting film for reflecting light is formed on the outer peripheral surface of the portion, and a light absorbing film for absorbing light is formed on the inner peripheral surface of the annular portion.

  The present invention is also a laser beam damper for blocking a laser beam, comprising a heat conduction member having a beam entrance and a spiral portion formed in a spiral shape, and light is emitted to the outer peripheral surface of the spiral portion. A light reflection film for reflection is formed, and a light absorption film for absorbing light is formed on the inner peripheral surface of the spiral portion.

  The laser device of the present invention includes a laser beam damper, a fundamental wave oscillator that oscillates a fundamental wave of laser light, and a wavelength conversion element that converts the fundamental wave of the laser beam oscillated by the fundamental wave oscillator into a harmonic. And a separator that separates the harmonic wave converted by the wavelength conversion element and the fundamental wave and outputs the fundamental wave to the laser beam damper.

  According to the present invention, when the beam is incident on the beam entrance, the beam repeats reflection and continues to travel in a circle. The beam can be expanded by using the outer peripheral surface and the inner peripheral surface of the annular portion, and the beam incident direction can take a large angle with respect to the normal line of the beam absorption surface. It can be dispersed and absorbed without being concentrated on the part. For this reason, the local heat_generation | fever in a laser beam absorption member is suppressed. Thereby, since the deterioration of the laser light absorbing member is suppressed, the life of the laser beam damper can be extended.

  Further, when the beam travels through the annular portion and reaches the beam entrance again, the beam traveling direction becomes the same direction as the new beam incident direction. For this reason, the beam traveling in the annular portion is not emitted again from the beam entrance. Thereby, the beam is confined and the return light can be reduced.

It is a figure which shows the structure of the laser beam damper of Example 1 of this invention. It is a figure which shows the detailed structure of the outer wall member of the laser beam damper of Example 1 of this invention. It is sectional drawing of the laser beam damper of Example 2 of this invention. It is sectional drawing of the laser beam damper of Example 3 of this invention. It is a block diagram of the laser apparatus containing the laser beam damper of the Example of this invention. It is a block diagram which shows an example of the conventional laser beam damper.

  Embodiments of a laser beam damper and a laser apparatus according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating the configuration of the laser beam damper according to the first embodiment. 1A is a perspective view of the laser beam damper, FIG. 1B is a cross-sectional view of the laser beam damper shown in FIG. 1A, and FIG. 1C is shown in FIG. It is a longitudinal cross-sectional view of a laser beam damper. 2A is a top view of the outer wall member, and FIG. 2B is a perspective view of the outer wall member.

  The laser beam damper according to the first embodiment shown in FIG. 1 includes an outer wall member 1 serving as an outer wall of an annular portion 13, a disk-shaped member 2 serving as an inner wall of the annular portion, an outer wall member 1, and a lid member 3 covering the disk-shaped member 2. And a cooling fan 4 for cooling the lid member 3.

  The outer wall member 1 and the disk-shaped member 2 are made of a member having high thermal conductivity and excellent heat resistance, for example, a metal material. The outer wall member 1 corresponds to the heat conducting member of the present invention. The outer wall member 1, the disk-shaped member 2, and the lid member 3 are joined together by a method such as welding and become an integrated state.

  As shown in FIGS. 2A and 2B, the outer wall member 1 has a beam entrance 11 for entering a laser beam and a circular flat portion 12 having a diameter larger than the diameter of the disk-shaped member 2. have. By arranging the disk-shaped member 2 concentrically with the center of the circular flat portion 12 on the flat portion 12 of the outer wall member 1, an annular ring portion 13 as shown in FIG. ing.

  A light reflection film for reflecting light is formed on the curved surface portion inside the outer wall member 1, and a light absorption film for absorbing light is formed on the curved surface portion of the disk-shaped member 2.

  The outer wall member 1 is made of stainless steel or aluminum alloy as a base, the surface roughness is reduced, and a metal film such as Al, Au, Ag, Pt, Cr, or a reflective film such as an alloy containing these as a main component is coated. By doing so, the reflectance of light is increased. The disk-shaped member 2 has a surface of stainless steel, aluminum alloy or the like as a light absorption film, a metal material such as Fe, Cr, Ni, Al, Zn, or an alloy or diamond like carbon (DLC) containing these as a main component. The carbon film is coated to improve light absorption and thermal conductivity. Furthermore, in order to increase the light absorption rate of the disk-shaped member 2, a method of increasing the surface roughness can be exemplified.

  The lid member 3 is composed of a heat sink for exhaust heat, and a material having excellent thermal conductivity such as Cu or Al is used. The lid member 3 is formed with an air cooling fin structure for promoting cooling. The cooling fan 4 cools the fins for air cooling.

  Next, the operation of the laser beam damper according to the first embodiment configured as described above will be described. First, a laser beam to be absorbed enters the laser beam damper from a beam entrance 11 formed in the outer wall member 1. The incident beam hits the outer wall member 1 and the disk-shaped member 2 from the tangential direction of the annular portion 13, and is reflected and absorbed by the curved surfaces of the outer wall member 1 and the disk-shaped member 2.

  Since the beam is incident on the outer wall member 1 and the disk-shaped member 2 at an angle close to the tangent to the annular structure, the area irradiated with the beam increases, and when the beam is absorbed, the beam is moved to the member. Damage is reduced. When the beam is reflected, the reflected beam is expanded and dispersed by the curved surface. That is, local concentration of heat on the member can be prevented and deterioration of the member can be suppressed.

  Next, the beam reflected without being absorbed by the member is irradiated to the surface of another member, and absorption and reflection of the beam occur similarly. By repeating the absorption and reflection of the beam, the beam is gradually converted into heat and absorbed until the intensity becomes zero while proceeding in a circular pattern. Further, under the annular structure, even when the unabsorbed beam goes around the annular portion 13 and reaches the beam entrance 11 again, the traveling direction of the beam is the same as that of the newly incident beam. It is a direction and does not exit from the beam entrance 11. For this reason, the beam is confined in the damper, and the generation of return light is suppressed.

  Furthermore, in Example 1, the light reflecting film and the light absorbing film are applied to the outer wall member 1 and the disk-shaped member 2, respectively. This makes it difficult for the heat of the beam to leak to the outer surface of the outer wall member 1, and further facilitates the transfer of heat due to beam absorption to the lid member 3 having the cooling fin structure via the disk-shaped member 2, enabling efficient cooling.

  In the first embodiment, the outer wall member 1 and the disk-shaped member 2 are provided with the light reflecting film and the light absorbing film, respectively. For example, uniform surface treatment is performed so that the overall beam reflectivity is about 70%. It is also possible to apply the method. In this method, the beam is absorbed little by little every time it hits the member and reflects while traveling through the annular structure. Further, since reflection is mainly used, it is possible to further extend the life of the laser beam damper without significant deterioration due to light absorption.

  As described above, according to the laser beam damper of the first embodiment, when the beam is incident on the beam incident port 11, the beam repeats reflection and continues to progress so as to draw a circle. The beam can be expanded by using the outer peripheral surface and the inner peripheral surface of the annular portion 13, and the incident direction of the beam can take a large angle with respect to the normal line of the beam absorption surface. It can be dispersed and absorbed without being concentrated in a part. For this reason, the local heat_generation | fever in a laser beam absorption member is suppressed. Thereby, since the deterioration of the laser light absorbing member is suppressed, the life of the laser beam damper can be extended.

  In the first embodiment, the outer wall member 1 and the disk-shaped member 2 are combined to form the annular portion 13. However, the disk-shaped member 2 may be deleted and the annular portion may be formed only on the outer wall member 1. .

  FIG. 3 is a sectional view of the laser beam damper according to the second embodiment of the present invention. In Example 1 shown in FIG. 1, the outer wall member 1 and the disk-shaped member 2 are combined to form an annular portion 13, and the annular portion 13 has a rectangular shape as shown in the sectional view of FIG. It was.

  On the other hand, as shown in FIG. 3, the laser beam damper according to the second embodiment includes the outer wall member 1a and the lid member 3a except for the disk-shaped member 2.

  An annular groove 13a, 13b is formed in the outer wall member 1a and the lid member 3a, and an annular ring structure having a round cross section is formed by disposing the groove 13a of the outer wall member 1a and the groove 13b of the lid member 3a to face each other. The part is formed. The annular grooves 13a and 13b are formed by devising the shape of an end mill for metal processing.

  Since the annular portion having an annular structure with a round cross section is formed, the deterioration of the light absorbing member is further reduced by the dispersion of the beam using the curved surface.

  FIG. 4 is a cross-sectional view of the laser beam damper according to the third embodiment of the present invention. This sectional view corresponds to the transverse sectional view shown in FIG.

  The laser beam damper according to the third embodiment includes an outer wall member 1b and a lid member 3a shown in FIG.

  As shown in FIG. 4, the outer wall member 1 b has a spiral portion 14 formed in a spiral shape with the beam incident port 11, and a light reflecting film for reflecting light is formed on the outer peripheral surface of the spiral portion 14. A light absorption film for absorbing light is formed on the inner peripheral surface of the spiral portion 14.

  According to such a configuration, a longer laser light absorption path can be secured, deterioration of the laser light absorbing member can be suppressed, and the life of the laser beam damper can be extended. At the same time, the return light of the laser beam can be greatly reduced.

  FIG. 5 is a configuration diagram of a laser apparatus including a laser beam damper according to an embodiment of the present invention. The laser device includes a fundamental wave oscillator 21, a lens 22, a wavelength conversion element 23, a lens 24, a separator 25, and a laser beam damper 26.

  The fundamental wave oscillator 21 oscillates the fundamental wave of the laser beam and outputs the fundamental wave to the wavelength conversion element 23 via the lens 22. The wavelength conversion element 23 converts the fundamental wave of the laser light oscillated by the fundamental wave oscillator 21 into a harmonic wave, and outputs the harmonic wave and the fundamental wave that could not be wavelength-converted to the separator 25.

  The separator 25 separates the harmonic wave converted by the wavelength conversion element 23 from the fundamental wave that could not be wavelength-converted, and outputs the fundamental wave to the laser beam damper 26. The laser beam damper 26 is the laser beam damper of the first to third embodiments, and absorbs the fundamental wave from the separator 25.

  As described above, the laser beam dampers of the first to third embodiments can be applied to the laser apparatus, and the effects of the laser beam dampers of the first to third embodiments can be obtained.

DESCRIPTION OF SYMBOLS 1 Outer wall member 2 Disk type member 3 Cover member 4 Cooling fan 5 Beam absorption part 6 Heat sink 11 Beam entrance 12 Flat part 13 Ring part 14 Spiral part 21 Fundamental wave oscillators 22 and 24 Lens
23 Wavelength conversion element 25 Separator 26 Laser beam damper

Claims (11)

A laser beam damper for blocking the laser beam,
A laser beam damper comprising a heat conducting member having a beam entrance and an annular portion formed in an annular shape. A laser beam damper for blocking the laser beam,
A laser beam damper, comprising: a heat conduction member having a beam entrance and a spiral portion formed in a spiral shape.   2. The laser beam damper according to claim 1, wherein a light reflecting film for reflecting light or a light absorbing film for absorbing light is uniformly formed on the surface of the annular portion.   3. The laser beam damper according to claim 2, wherein a light reflecting film for reflecting light or a light absorbing film for absorbing light is uniformly formed on the surface of the spiral portion.   A light reflecting film for reflecting light is formed on the outer peripheral surface of the annular portion, and a light absorbing film for absorbing light is formed on the inner peripheral surface of the annular portion. The laser beam damper according to claim 1. A disk-shaped member, and a lid member that covers the disk-shaped member and the heat conducting member,
The heat conductive member has a circular flat portion having a diameter larger than the diameter of the disk-shaped member, and the circular ring portion concentrically arranges the disk-shaped member on the flat portion of the heat conductive member. The laser beam damper according to claim 1, wherein the laser beam damper is formed. A lid member covering the heat conducting member;
An annular groove is formed in the heat conducting member and the lid member,
3. The laser beam damper according to claim 2, wherein the annular portion is formed by arranging the groove portion of the heat conducting member and the groove portion of the lid member to face each other.   The laser according to claim 1, wherein the light reflecting film is formed of any one of Al, Au, Ag, Pt, Cr, or an alloy containing these as a main component. Beam damper.   The laser according to claim 1, wherein the light absorption film is formed of any one of Fe, Cr, Ni, Al, Zn, or an alloy containing these as a main component. Beam damper.   The laser beam damper according to claim 1, wherein the light absorption film is formed of a carbon film. The laser beam damper according to any one of claims 1 to 10,
A fundamental oscillator that oscillates the fundamental wave of the laser beam;
A wavelength conversion element that converts the fundamental wave of the laser light oscillated by the fundamental wave oscillator into a harmonic, and
A separator that separates the harmonic wave and the fundamental wave converted by the wavelength conversion element and outputs the fundamental wave to the laser beam damper;
A laser device comprising:

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