JP2004085310A - Laser guide, laser guide disconnection detection system equipped therewith, and laser beam machining device equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser guide capable of detecting surely disconnection of an optical fiber for laser guide, and applicable to a large-size laser beam machining device. <P>SOLUTION: This laser guide is equipped with the optical fiber 21 for laser guide for guiding a laser beam L, and an optical fiber 23 for disconnection detection provided along the longitudinal direction of the optical fiber 21 for the laser guide. The optical fiber 23 for disconnection detection has a quartz core forming the fiber center and a plastic clad provided so as to cover the core. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser guide comprising a laser guide optical fiber for guiding laser light, and a disconnection detection optical fiber provided along the longitudinal direction of the laser guide optical fiber, and And a laser processing apparatus including the same.
[0002]
[Prior art]
There is a processing method for cutting or welding a metal such as iron or aluminum by using a high-power laser beam such as a YAG laser, which has begun to be applied to the manufacture of automobile bodies. In such processing, an optical fiber called a laser guide optical fiber is used to guide laser light emitted from a laser oscillator to a workpiece.
[0003]
By the way, when the laser guide optical fiber is disconnected for some reason, the laser light leaks from the disconnected portion. Since the leaked laser light has an energy enough to process the metal, it may heat an object other than the workpiece such as a protective tube, thereby causing an accident such as a fire. Therefore, there is a need for a laser guide disconnection detection system that detects the disconnection of the laser guide optical fiber.
[0004]
JP-A-56-17303, JP-A-58-130301, JP-A-60-101503, and JP-A-60-139241 disclose a technique for transmitting high-power light such as laser light. It is disclosed that a metal wire, a conductive paint, or the like is provided along the optical fiber, and the disconnection of the optical fiber is detected by the disconnection of the metal wire, the conductive paint, or the like.
[0005]
That is, in the disconnection detection system disclosed in the above publication, for example, as shown in FIG. 9, the laser guide optical fiber 21 ′ for guiding the laser light L ′ from the laser oscillator 10 ′ to the workpiece 30 ′. In addition, an electric wire 70 ′ is provided so as to form a closed circuit along the longitudinal direction and in which a monitor device 60 ′ for monitoring the energization state by a power source 50 ′ and an ammeter or the like is interposed. Accordingly, as shown in FIG. 10, when the laser guide optical fiber 21 ′ is disconnected and the laser light L ′ leaks, the electric wire 70 ′ is disconnected by the energy, thereby changing the energized state, so that the monitoring device 60 ′. Thus, the disconnection of the electric wire, that is, the disconnection of the laser guide optical fiber 21 'is detected. In such a case, the emission of the laser beam L' from the laser oscillator 10 'is immediately stopped. There.
[0006]
However, when the disconnection of the laser guide optical fiber 21 ′ is detected by the disconnection of the electric wire 70 ′ as described above, the melting point of the metal constituting the electric wire 70 ′ is equal to or lower than the temperature at which the melting point of the laser guide optical fiber 21 ′ increases. Need to be. Specifically, for example, when the laser guide optical fiber is a GI fiber, the temperature that rises due to the disconnection is about 200 to 300 ° C., so the melting point of the metal constituting the electric wire needs to be lower than that. Become. On the other hand, such a low melting point metal wire has a low mechanical strength and may be cut by deformation of external force or bending. In such a case, the laser guide optical fiber breakage detection system malfunctions. .
[0007]
[Problems to be solved by the invention]
It is also possible to configure a laser guide disconnection detection system using an optical fiber.
[0008]
For example, as shown in FIG. 11, a disconnection detection optical fiber 23 ′ is provided along the longitudinal direction of a laser guide optical fiber 21 ′ for guiding the laser light L ′ from the laser oscillator 10 ′ to the workpiece 30 ′. In addition, it is possible to configure a laser guide disconnection detection system in which a light source 24 'is disposed at one end of the optical fiber 23' for disconnection detection and a photodetector 25 'is disposed at the other end of the fiber. Accordingly, as shown in FIG. 12, when the laser guide optical fiber 21 ′ is disconnected and the laser light L ′ leaks, the energy of the disconnection detection optical fiber 23 ′ is disconnected by the energy, thereby the optical detector 25 ′. Since the light from the light source 24 'is not detected, the disconnection of the laser guide optical fiber 21' can be detected.
[0009]
Further, as shown in FIG. 13, the disconnection detection optical fiber 23 ′ is provided along the longitudinal direction of the laser guide optical fiber 21 ′ for guiding the laser light L ′ from the laser oscillator 10 ′ to the workpiece 30 ′. At the same time, one end of the disconnection detecting optical fiber 23 ′ is disposed in the laser light emitting portion 22 ′ and reflected by a lens system (not shown) out of the laser light L ′ from the laser guide optical fiber 21 ′. It is also possible to construct a laser guide breakage detection system in which a part of the object is incident thereon and the other fiber end is provided in the photodetector 25 ′, and as shown in FIG. When the optical fiber 21 ′ is disconnected and the laser light L ′ leaks, the disconnection detection optical fiber 23 ′ is disconnected by the energy, and the light is not detected by the optical detector 25 ′. It is possible to detect the disconnection of the guide optical fiber 21 '.
[0010]
However, if the disconnection detection optical fiber is made of quartz, the fiber strand of the disconnection detection optical fiber does not melt at the temperature that rises due to the disconnection of the laser guide optical fiber, and the resin coating part melts. Since the fiber strand is disconnected only when the strength is reduced and an external force is applied, there is a problem that it is difficult to reliably detect the disconnection of the optical fiber for laser guide.
[0011]
Also, if the optical fiber for disconnection detection is made of plastic, it will break at a temperature that rises due to the disconnection of the optical fiber for laser guide, but the light transmittance is inferior to that of quartz. If the fiber length of the optical fiber is long, it is difficult to detect light with a light detector, and thus there is a problem that it cannot be used for a laser processing apparatus that requires a long laser guide.
[0012]
The present invention has been made in view of the above points, and the object of the present invention is to reliably detect the disconnection of the laser guide optical fiber, and to propagate even if the fiber length of the disconnection detection optical fiber is long. It is an object of the present invention to provide a laser guide capable of detecting light to be detected, a laser guide disconnection detection system including the laser guide, and a laser processing apparatus including the laser guide.
[0013]
[Means for Solving the Problems]
In the present invention, a so-called polymer clad fiber having a core made of quartz and a clad made of plastic is used as an optical fiber for disconnection detection.
[0014]
Specifically, the first laser guide of the present invention includes a laser guide optical fiber for guiding laser light and a disconnection detection optical fiber provided along the longitudinal direction of the laser guide optical fiber. And comprising:
The disconnection detecting optical fiber has a quartz core that forms the center of the fiber, and a plastic clad provided to cover the core.
[0015]
According to the above configuration, when the core of the disconnection detecting optical fiber is made of quartz and the clad is made of plastic, and the laser guide optical fiber is disconnected, the laser beam leaks from the disconnected portion, and the disconnected portion is caused by the energy. As the temperature of the resin rises, the resin clad melts, and the light propagation state changes due to, for example, that light cannot be confined in the core and light cannot propagate through the disconnection detection optical fiber. The disconnection of the laser guide optical fiber can be reliably detected. Normally, since the core has a small diameter, the clad does not melt and only the core remains, and the melting of the clad breaks the disconnection detection optical fiber. The certainty of disconnection detection is supported.
[0016]
In addition, since the core through which the light propagates is made of quartz and can detect the propagating light even if the fiber length of the disconnection detecting optical fiber is long, the laser processing apparatus requires a long laser guide. Even can be applied.
[0017]
The first laser guide disconnection detection system of the present invention provided with the laser guide as described above,
An optical fiber for laser guide for guiding laser light;
An optical fiber for disconnection detection provided along the longitudinal direction of the optical fiber for laser guide;
A light incident means provided at one end of the optical fiber for disconnection detection, and makes light incident on the optical fiber for disconnection detection;
A light detection means for detecting light from the light incident means provided at the other fiber end of the disconnection detection optical fiber and propagating through the disconnection detection optical fiber;
A laser guide disconnection detection system comprising:
The disconnection detecting optical fiber has a quartz core that forms the center of the fiber, and a plastic clad provided to cover the core.
[0018]
In the first laser guide disconnection detection system of the present invention, the light incident means is provided so that a laser beam emitted from the laser guide optical fiber is incident on one fiber end of the disconnection detection optical fiber. It may be configured by an installation structure of the disconnection detecting optical fiber.
[0019]
The light incident means may be configured by a light source provided at one end of the disconnection detecting optical fiber. However, according to the above configuration, such a light source is unnecessary and the configuration is simplified. Can do.
[0020]
The second laser guide of the present invention includes a laser guide optical fiber for guiding laser light, and two disconnection detection optical fibers provided along the longitudinal direction of the laser guide optical fiber, Light is provided from one fiber end to the other fiber end of the two disconnection detecting optical fibers provided on the output end side of the laser guide optical fiber among the fiber ends of the two disconnection detecting optical fibers. A light guide means for guiding light,
Each of the two disconnection detection optical fibers has a quartz core that forms the center of the fiber, and at least one of the two disconnection detection optical fibers is provided so as to cover the core. It has a plastic clad.
[0021]
According to the above configuration, when at least one of the two disconnection detecting optical fibers is made of plastic, and the laser guide optical fiber is disconnected, the laser beam leaks from the disconnected portion, and the disconnected portion is caused by the energy. As the temperature of the resin rises, the resin clad melts, and the light propagation state changes due to, for example, that light cannot be confined in the core and light cannot propagate through the disconnection detection optical fiber. The disconnection of the laser guide optical fiber can be reliably detected. Normally, since the core has a small diameter, the clad does not melt and only the core remains, and the melting of the clad breaks the disconnection detection optical fiber. The certainty of disconnection detection is supported.
[0022]
Since both of the two disconnection detection optical fibers have a core made of quartz and can detect the propagating light even if the fiber length of the disconnection detection optical fiber is long, a long laser guide is used. Even a laser processing apparatus that requires the above can be applied.
[0023]
The disconnection detection optical fiber extends from the incident end to the exit end of the laser guide optical fiber and then folds back to return from the exit end to the entrance end. If the configuration of the laser guide is provided with a light detector, the optical fiber for disconnection detection may be broken at the folded portion, loss due to bending deformation occurs, and further, the optical fiber for disconnection detection Therefore, it is necessary to secure a space for this. However, according to the above configuration, since the disconnection detecting optical fiber is not bent and deformed at the folded portion, the disconnection detecting optical fiber is not bent, and loss due to bending deformation does not occur. Since it is not necessary to form the optical fiber for disconnection detection in a substantially arc shape, the folded portion can be reduced in size.
[0024]
The second laser guide disconnection detection system of the present invention provided with the laser guide as described above,
An optical fiber for laser guide for guiding laser light;
Two disconnection detection optical fibers provided along the longitudinal direction of the laser guide optical fiber;
Of the two disconnection detecting optical fibers, light is provided from one end of the two disconnection detecting optical fibers to the other end of the two optical fibers for detecting the disconnection. A light guiding means for guiding light;
Of the two disconnection detection optical fibers, one of the disconnection detection optical fibers is provided near the incident end of the laser guide optical fiber, and light is incident on the one disconnection detection optical fiber. Light incident means;
Of the two disconnection detection optical fibers, the light transmitted through the other disconnection detection optical fiber provided on the incident end side of the laser guide optical fiber among the fiber ends of the other disconnection detection optical fiber. A light detecting means for detecting light from the incident means;
A laser guide disconnection detection system comprising:
Each of the two disconnection detection optical fibers has a quartz core that forms the center of the fiber, and at least one of the two disconnection detection optical fibers is provided so as to cover the core. It has a plastic clad.
[0025]
The laser processing apparatus of the present invention includes the first or second laser guide disconnection detection system of the present invention as described above.
[0026]
【The invention's effect】
As described above, according to the present invention, the core of the disconnection detection optical fiber is made of quartz and the cladding is made of plastic, and when the laser guide optical fiber is disconnected, the resin cladding melts and the light Since the propagation state changes, it is possible to reliably detect the disconnection of the laser guide optical fiber.
[0027]
In addition, since the core through which the light propagates is made of quartz and can detect the propagating light even if the fiber length of the disconnection detecting optical fiber is long, the laser processing apparatus requires a long laser guide. Even can be applied.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0029]
(Embodiment 1)
FIG. 1 shows a laser processing apparatus A according to Embodiment 1 of the present invention.
[0030]
This laser processing apparatus A performs cutting and welding of metals such as iron and aluminum, and a laser oscillator 10 such as a YAG laser and a laser beam L attached to the laser oscillator 10 from the laser oscillator 10 to the workpiece 30. A cable-shaped laser guide 20 for guiding light.
[0031]
The laser guide 20 includes a laser guide optical fiber 21, a laser light emitting portion 22 attached to the workpiece 30 side end of the laser guide optical fiber 21, and an incident end to an exit end of the laser guide optical fiber 21. A disconnection detecting optical fiber 23 provided so as to extend along the laser guide optical fiber 21 and then return to return from the emission end to the incidence end. The laser guide optical fiber 21 and the disconnection detection optical fiber 23 of the laser guide 20 are covered with a flexible tube made of stainless steel (not shown).
[0032]
The disconnection detecting optical fiber 23 is composed of a quartz core that forms the center of the fiber, and a plastic clad such as an acrylic ultraviolet curable resin provided so as to cover the core. The optical fiber is coated with a coating layer such as nylon resin. A light source 24 as a light incident means is provided at one fiber end of the disconnection detecting optical fiber 23, and a light detector 25 as a light detection means is provided at the other fiber end. A laser guide disconnection detection system S is constituted by the optical fiber 21, the disconnection detection optical fiber 23, the light source 24, and the photodetector 25.
[0033]
This laser processing apparatus A normally performs processing by emitting laser light L from a laser oscillator 10 from a laser light emitting portion 22 toward a workpiece 30 through a laser guide optical fiber 21. . At this time, light is incident on the one end of the disconnection detecting optical fiber 23 from the light source 24, and the light propagates through the core of the disconnection detecting optical fiber 23 and is detected by the photodetector 25 at the other end of the fiber. The
[0034]
According to the above configuration, when the core of the disconnection detecting optical fiber 23 is made of quartz and the clad is made of plastic, and the laser guide optical fiber 21 is disconnected as shown in FIG. The light L leaks, the temperature of the broken portion rises due to the energy, and the resin coating layer and the clad melt, thereby making it impossible to confine the light in the core, for example, and the light propagates through the break detection optical fiber 23 Since the light propagation state changes due to reasons such as being impossible, the disconnection of the laser guide optical fiber 21 can be reliably detected. In general, since the core has a small diameter, the clad does not melt and only the core does not remain, and the melting of the clad causes the disconnection detecting optical fiber 23 to be broken. The reliability of 21 disconnection detection is supported.
[0035]
In addition, since the core through which the light propagates is made of quartz and the propagation light can be detected even if the fiber length of the disconnection detecting optical fiber 23 is long, the laser processing apparatus A has a long laser guide 20. May be required.
[0036]
(Embodiment 2)
FIG. 3 shows a laser processing apparatus A according to Embodiment 2 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals.
[0037]
In this laser processing apparatus A, the laser guide 20 includes a laser guide optical fiber 21, a laser light emitting portion 22 attached to an end of the laser guide optical fiber 21 on the emission end side, and a laser guide optical fiber 21. Two disconnection detecting optical fibers 23a and 23b provided along the laser guide optical fiber 21 from the laser oscillator 10 side end to the laser light emitting portion 22 are provided.
[0038]
A light source 24 as a light incident means is provided on the incident end side of the laser guide optical fiber 21 among the fiber ends of one of the two disconnection detection optical fibers 23a and 23b. In addition, the optical detector 25 serving as a light detecting means is located closer to the incident end side of the laser guide optical fiber among the fiber ends of the other disconnection detecting optical fiber 23b of the two disconnection detecting optical fibers 23a and 23b. Is provided.
[0039]
As shown in FIGS. 4 and 5, the laser light emitting portion 22 is provided with a bottomed cylindrical folded portion 40. In the folded portion 40, fiber end portions on the emission end side of the two disconnection detecting optical fibers 23a and 23b are inserted, and a prism 41 is provided in the vicinity of the bottom. Further, both disconnection detecting optical fibers are provided. A lens 42 is provided between each of 23 a and 23 b and the prism 41. The prism 41 is formed in a triangular prism having an isosceles triangle with a substantially right-angled cross section. A reflective coating 41a is applied to the surface corresponding to the hypotenuse, and the surface corresponding to the base is opposed to the optical fibers 23a and 23b for detecting both disconnections. Are arranged to be. As a result, the light from the light source 24 is reflected by the prism 41 via the lens 42 through the one disconnection detecting optical fiber 23a, and is incident on the other disconnection detecting optical fiber 23b to be detected by the photodetector 25. It is configured to reach. 4 and 5, the lens system for emitting laser light and the flexible tube are not shown.
[0040]
Other configurations are the same as those of the first embodiment.
[0041]
As in the first embodiment, the disconnection detection optical fiber 23 extends from the incident end to the exit end of the laser guide optical fiber 21 and then folds back to return from the exit end to the entrance end. With the configuration, the disconnection detection optical fiber 23 may be broken at the folded portion, loss due to bending deformation occurs, and the disconnection detection optical fiber 23 needs to be formed in a substantially arc shape. Therefore, it is necessary to secure a space for that purpose. However, according to the above configuration, the disconnection detecting optical fibers 23a and 23b are not bent and deformed by the folded portion 40, so that the disconnection detecting optical fibers 23a and 23b are not bent and a loss due to the bending deformation is caused. Further, since the disconnection detecting optical fibers 23a and 23b do not need to be formed in a substantially arc shape, the folded portion can be made small.
[0042]
Other operations and effects are the same as those of the first embodiment.
[0043]
(Embodiment 3)
FIG. 6 shows a laser beam emitting part of a laser processing apparatus A according to Embodiment 3 of the present invention. In addition, about the same part as Embodiment 1 and 2, it shows with the same code | symbol.
[0044]
In the laser processing apparatus A, a bottomed cylindrical folded portion 40 is provided in the laser light emitting portion 22 as shown in FIG. In the folded portion 40, fiber end portions on the emission end side of the two disconnection detecting optical fibers 23a and 23b are inserted, a mirror 43 is provided in the vicinity of the bottom, and both disconnection detecting optical fibers are provided. A lens 42 is provided between each of 23 a and 23 b and the mirror 43. The mirror 43 is formed in a shape in which a V-shaped groove is formed in a cube, and each surface of the V-shaped groove forms a mirror surface 43a having an angle of 45 ° with respect to each mirror surface 43a. The disconnection detecting optical fibers 23a and 23b are arranged in a direction that forms an angle of 45 °. As a result, the light from the light source 24 is reflected by the mirror 43 via the lens 42 through one of the disconnection detection optical fibers 23a, and is incident on the other disconnection detection optical fiber 23b. It is configured to reach.
[0045]
Other configurations, operations, and effects are the same as those of the second embodiment.
[0046]
(Embodiment 4)
FIG. 7 shows a laser processing apparatus A according to Embodiment 4 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals.
[0047]
In the laser processing apparatus A, in the laser guide 20, a disconnection detection optical fiber 23 is provided along the laser guide optical fiber 21 from the incident end of the laser guide optical fiber 21 to the laser light emitting portion 22. One end of one end of the disconnection detecting optical fiber 23 is disposed inside the laser light emitting portion 22 and a part of the laser light L emitted from the laser guide optical fiber 21 reflected by a lens system (not shown) is present there. A light detector 25 as a light detecting means is provided at the other fiber end. That is, the light incident means is constituted by the installation structure of the disconnection detection optical fiber 23 provided so that the laser light L emitted from the laser guide optical fiber 21 is incident on one end of the disconnection detection optical fiber 23. ing. Other configurations are the same as those of the first embodiment.
[0048]
According to the above configuration, as in the first embodiment, as shown in FIG. 8, when the laser guide optical fiber 21 is disconnected, the laser light L leaks from the disconnected portion, and the energy of the disconnected portion is caused by the energy. The temperature rises, the resin coating layer and the clad melt, and light cannot be confined in the core, so that the light cannot propagate through the disconnection detection optical fiber 23. Therefore, the laser guide optical fiber 21 is surely provided. Can be detected.
[0049]
Further, since a light source for the disconnection detecting optical fiber 23 is not required, the apparatus configuration can be simplified.
[0050]
Other operations and effects are the same as those of the first embodiment.
[0051]
(Other embodiments)
In the first to fourth embodiments, the disconnection detecting optical fiber 23 has a resin layer. However, the present invention is not particularly limited thereto, and may be composed only of a quartz core and a resin clad. Good.
[0052]
In the second and third embodiments, each of the two disconnection detecting optical fibers 23a and 23b has a quartz core and a plastic clad. However, the present invention is not particularly limited to this. Alternatively, either one may have a quartz core and cladding.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a laser processing apparatus according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a state when a laser guide optical fiber of the laser processing apparatus according to the first embodiment of the present invention is cut.
FIG. 3 is a cross-sectional view of a laser beam emitting portion of a laser processing apparatus according to Embodiment 2 of the present invention.
FIG. 4 is a cross-sectional view of a laser beam emitting portion of a laser processing apparatus according to Embodiment 2 of the present invention.
FIG. 5 is a cross-sectional view of a folded portion in a laser beam emitting portion of a laser processing apparatus according to Embodiment 2 of the present invention.
FIG. 6 is a configuration diagram of a laser processing apparatus according to Embodiment 3 of the present invention.
FIG. 7 is a configuration diagram of a laser processing apparatus according to Embodiment 4 of the present invention.
FIG. 8 is an explanatory diagram showing a state when a laser guide optical fiber of a laser processing apparatus according to a fourth embodiment of the present invention is cut.
FIG. 9 is a configuration diagram of a laser processing apparatus configured to detect disconnection of an optical fiber for laser guide with an electric wire.
FIG. 10 is an explanatory diagram showing a state when the laser guide optical fiber of the laser processing apparatus configured to detect disconnection of the laser guide optical fiber with an electric wire is cut.
FIG. 11 is a configuration diagram of a first laser processing apparatus configured to detect a disconnection of a laser guide optical fiber using an optical fiber.
FIG. 12 is an explanatory diagram showing a state when the laser guide optical fiber of the first laser processing apparatus in which the disconnection of the laser guide optical fiber is detected by the optical fiber is cut.
FIG. 13 is a configuration diagram of a second laser processing apparatus configured to detect a disconnection of a laser guide optical fiber using an optical fiber.
FIG. 14 is an explanatory diagram showing a state when the laser guide optical fiber of the second laser processing apparatus in which the disconnection of the laser guide optical fiber is detected by the optical fiber is cut.
[Explanation of symbols]
10, 10 ′ Laser oscillator 20 Laser guide 21, 21 ′ Laser guide optical fiber 22, 22 ′ Laser light emitting portions 23, 23a, 23b, 23 ′ Disconnection detection optical fiber 24, 24 ′ Light source (light incident means)
25, 25 'light detector (light detection means)
30, 30 'Workpiece 40 Folding part 41 Prism 41a Reflective coating 42 Lens 43 Mirror 43a Mirror surface 50' Power supply 60 'Monitor device 70' Electric wire A Laser processing device L, L 'Laser light S Laser guide disconnection detection system

Claims (6)

A laser guide comprising: a laser guide optical fiber for guiding laser light; and a disconnection detection optical fiber provided along the longitudinal direction of the laser guide optical fiber,
The disconnection detecting optical fiber has a quartz core forming the center of the fiber, and a plastic clad provided so as to cover the core. A laser guide optical fiber for guiding laser light, two disconnection detection optical fibers provided along the longitudinal direction of the laser guide optical fiber, and the two disconnection detection optical fibers. A light guide means for guiding light from one fiber end to the other fiber end of the two disconnection detecting optical fibers provided on the output end side of the laser guide optical fiber among the fiber ends; A laser guide provided,
Each of the two disconnection detection optical fibers has a quartz core that forms the center of the fiber, and at least one of the two disconnection detection optical fibers is provided so as to cover the core. A laser guide having a plastic clad. An optical fiber for laser guide for guiding laser light;
An optical fiber for disconnection detection provided along the longitudinal direction of the optical fiber for laser guide;
A light incident means provided at one end of the optical fiber for disconnection detection, and makes light incident on the optical fiber for disconnection detection;
A light detection means for detecting light from the light incident means provided at the other fiber end of the disconnection detection optical fiber and propagating through the disconnection detection optical fiber;
A laser guide disconnection detection system comprising:
The disconnection detecting optical fiber has a quartz core that forms the center of the fiber, and a plastic clad provided so as to cover the core. In the laser guide disconnection detection system according to claim 3,
The light incident means is configured by an installation structure of the disconnection detection optical fiber provided so that laser light emitted from the laser guide optical fiber is incident on one end of the disconnection detection optical fiber. Laser guide disconnection detection system characterized by that. An optical fiber for laser guide for guiding laser light;
Two disconnection detection optical fibers provided along the longitudinal direction of the laser guide optical fiber;
Of the two disconnection detecting optical fibers, light is provided from one end of the two disconnection detecting optical fibers to the other end of the two optical fibers for detecting the disconnection. A light guiding means for guiding light;
Of the two disconnection detection optical fibers, one of the disconnection detection optical fibers is provided near the incident end of the laser guide optical fiber, and light is incident on the one disconnection detection optical fiber. Light incident means;
Of the two disconnection detection optical fibers, the light transmitted through the other disconnection detection optical fiber provided on the incident end side of the laser guide optical fiber among the fiber ends of the other disconnection detection optical fiber. A light detecting means for detecting light from the incident means;
A laser guide disconnection detection system comprising:
Each of the two disconnection detection optical fibers has a quartz core that forms the center of the fiber, and at least one of the two disconnection detection optical fibers is provided so as to cover the core. A laser guide disconnection detection system having a plastic clad. A laser processing apparatus comprising the laser guide disconnection detection system according to claim 3.

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