JP2013025044A - Processing structure for reflected return light and laser device - Google Patents

Abstract

An object of the present invention is to provide a reflected return light processing structure capable of preventing damage to an optical connector and a laser device using the same.
A reflected return light processing structure is connected between an optical connector and an optical isolator and processes reflected return light from the optical isolator, and is input to the input side of the optical isolator. And a projection 41a that absorbs the reflected return light by blocking at least part of the reflected return light from the optical isolator traveling in a direction inclined with respect to the traveling direction of the light. A processing member 41 is provided.
[Selection] Figure 2

Description

  The present invention relates to a processing structure for reflected return light from an optical isolator and a laser apparatus.

  For example, in a laser apparatus for laser processing, there is a case where the emission end portion of the delivery optical fiber is burned by reflected return light from the processing target. In order to prevent this, a technique of disposing a shield having an opening in a lens optical system provided at a light emitting end of a delivery optical fiber is disclosed (see Patent Document 1). This shielding body blocks the reflected return light, so that the reflected return light does not reach the exit end of the delivery optical fiber.

  In recent years, the output laser beam intensity of laser devices for laser processing has been increasing. Therefore, the high intensity reflected return light from the object to be processed may travel back through the delivery optical fiber and reach the laser light source, causing the laser light source to burn out. In order to prevent this, it is effective to provide an optical isolator on the light emitting end side of the delivery optical fiber.

  In an inline type optical isolator, reflected return light is emitted inside the optical isolator, which may cause a problem. In order to solve this problem, a technique is disclosed in which reflected return light is converted into heat and processed inside the optical isolator (see Patent Document 2).

JP 63-163307 A JP 2007-183419 A

  As described above, the laser isolator is prevented from being burned out by the reflected return light by the optical isolator, and thus it has been considered that the problem of the reflected return light in the laser apparatus for laser processing has been solved.

  However, when the output laser light intensity of the laser device is extremely high, the temperature of the optical connector provided at the tip of the delivery optical fiber becomes extremely high and may be damaged. It was found.

  The present invention has been made in view of the above, and an object of the present invention is to provide a reflected return light processing structure capable of preventing the optical connector from being damaged, and a laser device using the same.

  In order to solve the above-described problems and achieve the object, a reflected return light processing structure according to the present invention is connected between an optical connector and an optical isolator, and processes the reflected return light from the optical isolator. A reflected return light processing structure, which transmits light input to the input side of the optical isolator and transmits reflected light from the optical isolator that travels in a direction inclined with respect to the traveling direction of the light. A processing member having a projection that blocks at least part of the light beam and absorbs the reflected return light.

  In the reflected return light processing structure according to the present invention as set forth in the invention described above, the protrusion is formed along the inner periphery of the tubular processing member.

  The reflected return light processing structure according to the present invention includes a plurality of the processing members connected along the traveling direction of the light input to the input side of the optical isolator in the above invention.

  In the reflected return light processing structure according to the present invention, the processing member is made of aluminum which is black anodized.

  The reflected return light processing structure according to the present invention further includes an extension member provided between the optical isolator and the processing member.

  In the above invention, the reflected return light processing structure according to the present invention further includes a heat dissipation member provided on the processing member on the optical connector side.

  The reflected return light processing structure according to the present invention further includes a heat dissipating member provided so as to surround the processing member.

  The laser device according to the present invention includes a laser light source that outputs laser light, a delivery optical fiber that is connected to the laser light source and transmits the laser light, and is connected to the delivery optical fiber, and the delivery optical fiber is connected to the laser light source. An optical connector for outputting the transmitted laser light, a reflected return light processing structure connected to the optical connector, and an optical isolator connected to the reflected return light processing structure.

  According to the present invention, it is possible to prevent the optical connector from being damaged.

FIG. 1 is a schematic configuration diagram of a laser apparatus to which the processing structure according to the first embodiment is applied. FIG. 2 is a schematic cross-sectional view of the processing structure shown in FIG. FIG. 3 is a schematic cross-sectional view of the processing structure according to the second embodiment. FIG. 4 is a diagram illustrating a temporal change in the temperature of the optical connector in the example and the comparative example. FIG. 5 is a schematic cross-sectional view of the processing structure according to the third embodiment. FIG. 6 is a schematic cross-sectional view of the processing structure according to the fourth embodiment. FIG. 7 is a schematic cross-sectional view of the processing structure according to the fifth embodiment.

  Embodiments of a reflected return light processing structure and a laser apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In the drawings, the same or corresponding elements are denoted by the same reference numerals as appropriate. In addition, it should be noted that the drawings are schematic, and the thicknesses and ratios of the layers may differ from actual ones. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained. Therefore, specific dimensions should be determined in consideration of the following description.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a laser apparatus to which the processing structure according to the first embodiment is applied. As shown in FIG. 1, the laser apparatus 100 includes a laser light source 10, a delivery optical fiber 20, an optical connector 30, a reflected return light processing structure (hereinafter, processing structure) 40, and an optical isolator 50. I have.

  The laser light source 10 is an optical fiber laser using, for example, a double-clad optical fiber to which ytterbium (Yb), which is a rare earth metal element, is added. The laser light source 10 outputs laser light having a wavelength of about 1080 nm and an intensity of 100 W or more, for example, 300 W. The laser light source 10 is not limited to an optical fiber laser, and may be a solid laser or a gas laser.

  The delivery optical fiber 20 is connected to the laser light source 10 and transmits laser light output from the laser light source in a single mode or a multimode.

  The optical connector 30 is connected to the tip of the delivery optical fiber 20. The optical connector 30 includes an optical system in a metal housing, and outputs collimated light or condensed laser light transmitted through the delivery optical fiber 20.

  The processing structure 40 is connected to the optical connector 30. The processing structure 40 allows the laser beam output from the optical connector 30 to pass through. The processing structure 40 will be described in detail later.

  The optical isolator 50 is connected to the processing structure 40. In use, the optical isolator 50 is disposed so as to face a plate material P made of, for example, metal, which is a processing target for laser processing. The optical isolator 50 transmits the laser beam that has passed through the processing structure 40 and outputs the laser beam as the laser beam L1. The output laser beam L1 reaches the plate material P and melts the plate material P, for example. Thus, the plate material P is processed.

  Here, the laser light L1 that has reached the plate material P may be reflected by the plate material P and returned to the optical isolator 50 as reflected return light RL1. The intensity of the reflected return light RL1 may reach approximately 100% of the intensity of the laser light L1. In this case, the action of the optical isolator 50 prevents the reflected return light RL1 from returning to the laser light source 10 via the optical connector 30 and the delivery optical fiber 20.

  Next, the configuration and operation of the processing structure 40 will be specifically described. FIG. 2 is a schematic cross-sectional view of the processing structure shown in FIG. As shown in FIG. 2, the processing structure 40 includes a plurality of processing members 41 and a joining portion 42. In the processing structure 40 according to the first embodiment, the number of processing members 41 is 19.

  The processing member 41 is tubular and has a protrusion 41a on the inside. The protrusion 41 a is formed along the inner periphery of each processing member 41 over the entire inner periphery. The processing members 41 are connected to each other along the traveling direction of the laser light L <b> 1 while being fitted to each other to constitute the processing structure 40. The inner diameters of the protrusions 41a are substantially the same, and are set to an inner diameter that does not interfere with at least the laser light L1 output from the optical connector 30. Therefore, the laser beam L1 hardly attenuates, and for example, 99% or more of the light intensity can pass through the processing structure 40.

  The joining portion 42 is disposed between the connected processing member 41 and the optical connector 30 and is configured to be fitted to each of the processing member 41 and the optical connector 30. The processing member 41 and the joining portion 42 are made of a metal such as aluminum whose surface is subjected to black alumite treatment for light absorption. By the black alumite treatment, a light absorption rate of, for example, about 80% or more can be realized at the wavelength of the laser light L1.

  Next, the operation of the processing structure 40 will be specifically described. First, the laser light L <b> 1 output from the optical connector 30 passes through the processing structure 40 along the central axis X of the processing structure 40. The laser light L1 further passes through and outputs the optical part 50a of the optical isolator 50, and reaches the plate material P shown in FIG.

  When the reflected return light RL1 reflected from the plate member P returns to the optical isolator 50, the action of the optical isolator 50 prevents the reflected return light RL1 from returning to the laser light source 10 via the optical connector 30 and the delivery optical fiber 20. The

  However, the optical unit 50a of the optical isolator 50 is usually configured using a birefringent crystal, and realizes the function of the optical isolator using the walk-off effect of the birefringent crystal. For this reason, the reflected return light RL1 that has returned to the optical isolator 50 does not return to the direction in which the laser light L1 has propagated (the direction of the central axis X) after passing through the optical unit 50a of the optical isolator 50. The travel proceeds in a direction inclined with respect to X. As described above, the reflected return light RL1 may be about 100% of the intensity of the laser light L1, for example, 300 W. Therefore, when the reflected return light RL1 travels in a direction inclined with respect to the central axis X and reaches the optical connector 30, the reflected return light RL1 hits the housing of the optical connector 30 to increase the temperature thereof and damage the optical connector 30 in some cases. is there.

  On the other hand, in the laser apparatus 100, the processing structure 40 according to the first embodiment is provided between the optical isolator 50 and the optical connector 30. As a result, the reflected return light RL1 traveling in a direction inclined with respect to the central axis X is partially reflected and absorbed by the projection 41a of the processing member 41 so that it is irregularly reflected and absorbed, and its intensity gradually attenuates. . As a result, even if the reflected return light RL1 hits the housing of the optical connector 30, its strength is sufficiently attenuated, so that the temperature rise of the optical connector 30 is suppressed and damage is prevented.

  In this processing structure 40, the inner diameters of the protrusions 41a of the processing members 41 are substantially the same. Therefore, as shown in FIG. 2, the protrusion 41a of the processing member 41 on the optical isolator 50 side has a small area that blocks the light beam of the reflected return light RL1, and becomes the protrusion 41a of the processing member 41 on the optical connector 30 side. Accordingly, the area that blocks the light beam of the reflected return light RL1 increases. Conversely, the reflected return light RL1 has a high intensity on the optical isolator 50 side and decreases in intensity as it travels to the optical connector 30 side. As described above, the magnitude relationship between the intensity of the reflected return light RL1 and the area blocked by the protrusion 41a is reversed along the traveling direction of the reflected return light RL1, and thus is absorbed by each processing member 41. The difference between the amount of light and the accompanying temperature rise is reduced. As a result, the difference in temperature distribution within the processing structure 40 is also reduced. As a result, a decrease in the light processing capability of the processing structure 40 is suppressed.

  As described above, in the laser device 100, since the processing structure 40 according to the first embodiment is provided between the optical isolator 50 and the optical connector 30, an increase in the temperature of the optical connector 30 is suppressed, Damage is prevented.

(Embodiment 2)
FIG. 3 is a schematic cross-sectional view of a processing structure 40A according to Embodiment 2 of the present invention. As illustrated in FIG. 3, the processing structure 40 </ b> A is the processing structure 40 including the processing member 41 and the joint portion 42 illustrated in FIG. 2, and further includes an extension member 43. The extension member 43 is provided between the connected processing member 41 and the optical isolator. The extension member 43 has, for example, a circular tube shape.

  In this processing structure 40A, the inclination angle of the reflected return light RL1 that has passed through the optical unit 50a of the optical isolator 50 with respect to the traveling direction of the laser light L1 (that is, the central axis X) is the same as in the processing structure 40. However, in this processing structure 40A, by providing the extension member 43, the area where the projection 41a of each processing member 41 blocks the light beam of the reflected return light RL1 becomes larger than in the case of the processing structure 40. Therefore, the reflected return light RL1 can be further absorbed and processed. If the extension member 43 is made of a material having high thermal conductivity such as aluminum, the heat of each processing member 41 generated along with the absorption of the reflected return light RL1 is dissipated by the extension member 43. The light processing capability of 40A is further improved. As a result, the laser beam L1 having a higher intensity can be used for a longer time.

  Next, as an example of the present invention, a processing structure having the configuration of the second embodiment was manufactured and connected between the optical isolator and the optical connector. Then, the temperature of the housing of the optical connector was measured while inputting a laser beam that simulated the reflected return light from the output side of the optical isolator. On the other hand, as a comparative example, the optical isolator and the optical connector were directly connected by a connecting member, and the temperature of the optical connector casing was measured while inputting laser light from the output side of the optical isolator.

  An optical isolator manufactured by EOT (Electro-Optics Technology) was used as the optical isolator. Further, as a delivery optical fiber and an optical connector, a QCS optical fiber cable with an optical connector manufactured by Optoscand was used. Moreover, what was provided with the process member which consists of aluminum which performed the black alumite process, the junction part, and the extension member was used as a process structure. The outer diameter of the processing member was 40 mm, the inner diameter was 28 mm, and the inner diameter of the protrusion was 9 mm. The thickness of the processing member was 15 mm. Twenty-seven processing members were connected, and the length of the extension member was 300 mm. The wavelength of the laser beam was about 1080 nm and the intensity was about 22W.

  FIG. 4 is a diagram illustrating a temporal change in the temperature of the optical connector in the example and the comparative example. The time on the horizontal axis indicates that the laser beam input start time is zero seconds. In addition, the vertical axis indicates the temperature when an intensity of 22 W laser light is input in terms of the case where a 300 W laser light is input. As shown in FIG. 4, in the case of the comparative example, the temperature of the optical connector increased rapidly after the start of laser light input, and was converted when it reached 320 ° C. or more before 100 seconds had elapsed. On the other hand, in the case of the example, the temperature of the optical connector hardly increased even after the start of laser light input, and was converted to 50 ° C. or less even after 800 seconds.

  Usually, in the case of laser processing, the time for outputting laser light is several tens of seconds to several hundreds of seconds. The optical connector is preferably maintained at a temperature of 50 ° C. or lower. Therefore, from the result of FIG. 4, in the case of the example, even if laser light having an intensity of 300 W is input as reflected return light from the output side of the optical isolator, the processing structure suitably suppresses the temperature rise of the optical connector It was confirmed that

(Embodiment 3)
FIG. 5 is a schematic cross-sectional view of a processing structure 40B according to Embodiment 3 of the present invention. As shown in FIG. 5, the processing structure 40 </ b> B further includes a heat radiating member 44 in the processing structure 40 </ b> A including the processing member 41, the joint 42, and the extension member 43 shown in FIG. 3. The heat dissipation member 44 is provided on the optical connector 30 side of the connected processing member 41. The heat radiating member 44 has, for example, a circular tube shape and is made of a material having high thermal conductivity such as aluminum.

  In this processing structure 40B, since the heat radiation member 44 is further provided on the optical connector 30 side, the temperature rise of the optical connector 30 can be further suppressed in addition to the effect of the processing structure 40A. As a result, the laser beam L1 having a higher intensity can be used for a longer time.

(Embodiment 4)
FIG. 6 is a schematic cross-sectional view of a processing structure 40C according to Embodiment 4 of the present invention. As shown in FIG. 6, the processing structure 40 </ b> C further includes a heat dissipation member 45 in the processing structure 40 </ b> A including the processing member 41, the joining portion 42, and the extension member 43 shown in FIG. 3. The heat radiating member 45 has a tube shape surrounding the connected processing members 41 and is made of a material having high thermal conductivity such as aluminum.

  In this processing structure 40C, the heat of each processing member 41 is further radiated by the heat dissipation member 45, so that the optical processing capability of the processing structure 40C is further improved in addition to the effects of the processing structure 40A. As a result, the laser beam L1 having a higher intensity can be used for a longer time.

(Embodiment 5)
FIG. 7 is a schematic cross-sectional view of a processing structure 40D according to Embodiment 5 of the present invention. As shown in FIG. 7, the processing structure 40 </ b> D includes one processing member 41, a joining portion 42, and an extension member 43.

  Like this process structure 40D, the structure provided with the one process member 41 in which the protrusion part 41a was formed inside may be sufficient. The number of processing members 41 provided in the processing structure is not particularly limited, and the intensity of the laser light L1, the assumed intensity of the reflected return light RL1, the time of laser processing, the heat dissipation of the extension member 43 and the heat dissipation members 44 and 45. Depending on the capability, the upper limit value of the temperature of the optical connector 30, and the like, the reflected return light RL1 can be set to be attenuated to such an extent that the temperature of the optical connector 30 is not increased and damaged.

  In the above embodiment, the protrusion is formed over the entire inner periphery of the processing member. However, if the protrusion is formed at a position on the inner periphery that can block the reflected return light. Since it is good, it does not necessarily need to be formed over the entire inner periphery, for example, it may be formed in part.

  Further, the present invention is not limited by the above embodiment. What comprised each component of said each embodiment suitably was also included in this invention. For example, in the fourth embodiment, the heat radiating member 44 of the third embodiment may be provided. Or you may delete the extending member 43 from Embodiment 3-5. In addition, other alternative embodiments, examples, operational techniques, and the like made by those skilled in the art based on the above-described embodiments are all included in the present invention.

DESCRIPTION OF SYMBOLS 10 Laser light source 20 Delivery optical fiber 30 Optical connector 40, 40A, 40B, 40C, 40D Processing structure 41 Processing member 41a Protrusion part 42 Joining part 43 Extension member 44, 45 Heat radiation member 50 Optical isolator 50a Optical part 100 Laser apparatus L1 Laser Light P Plate material RL1 Reflected return light X Central axis

Claims (8)

A reflected return light processing structure that is connected between an optical connector and an optical isolator and processes reflected return light from the optical isolator,
The light input to the input side of the optical isolator is allowed to pass, and at least part of the light beam of reflected return light from the optical isolator traveling in a direction inclined with respect to the traveling direction of the light is blocked to return the reflected light. A reflected return light processing structure comprising a processing member having a protrusion that absorbs light.   2. The reflected return light processing structure according to claim 1, wherein the protrusion is formed along an inner periphery of the tubular processing member.   The reflected return light processing structure according to claim 1, further comprising a plurality of the processing members coupled along a traveling direction of light input to an input side of the optical isolator.   4. The reflected return light processing structure according to claim 1, wherein the processing member is made of aluminum subjected to black alumite treatment. 5.   5. The reflected return light processing structure according to claim 1, further comprising an extending member provided between the optical isolator and the processing member. 6.   The reflected return light processing structure according to any one of claims 1 to 5, further comprising a heat dissipating member provided on the processing member on the optical connector side.   The reflected return light processing structure according to any one of claims 1 to 6, further comprising a heat radiating member provided so as to surround the processing member. A laser light source for outputting laser light;
A delivery optical fiber connected to the laser light source and transmitting the laser light;
An optical connector connected to the delivery optical fiber and outputting the laser light transmitted through the delivery optical fiber;
The reflected return light processing structure according to any one of claims 1 to 7, which is connected to the optical connector;
An optical isolator connected to the reflected return light processing structure;
A laser device comprising:

Images