Beam coupler

Abstract

The present invention provides a beam coupler that can ensure high transmission quality. The present invention is provided with: an emission unit (230) from which condensed laser light (L) is emitted toward a transmission fiber (F2); an emission-side connector unit (260) that faces the emission unit (230) in the direction of propagation of the laser light (L) and holds the transmission fiber (F2) on which the laser light (L) is incident; a position adjustment unit for adjusting the position of the emission-side connector unit (260); and a bellows (280) that is connected to the emission unit (230) and the emission-side connector unit (260) and covers the gap between the emission unit (230) and the emission-side connector unit (260). The bellows (280) is capable of deforming so as to allow movement of the emission-side connector unit (260) relative to the emission unit (230).

Description

Beam coupler

[0001] This disclosure relates to a beam coupler.

[0002] For example, Patent Document 1 discloses a fiber coupler that makes a beam emitted from a receiving fiber enter a transmission fiber through a focusing lens. The fiber coupler of Patent Document 1 includes an adjustment mechanism that moves (rotates) the position of the focusing lens to adjust the focal point of the focusing lens.

[0003] Japanese Patent No. 6388920

[0004] However, in the fiber coupler of Patent Document 1, since it is necessary to move (rotate) the position of the focusing lens, the gap from the receiving fiber to the transmission fiber is widely open, and there is a concern that foreign matter initially present inside the housing may adhere to the receiving fiber, the focusing lens, or the transmission fiber, deteriorating the transmission quality.

[0005] This disclosure has been made in view of such circumstances, and an object thereof is to provide a beam coupler capable of ensuring high transmission quality.

[0006] To solve the above problems, the beam coupler of this disclosure employs the following means. The beam coupler according to one aspect of this disclosure includes an emission part from which the condensed laser light is emitted toward the transmission fiber, a connector part that faces the emission part in the traveling direction of the laser light and holds the transmission fiber into which the laser light enters, a position adjustment part for adjusting the position of the connector part, and a cover part that is connected to the emission part and the connector part and covers the gap between the emission part and the connector part. The cover part is deformable so as to allow the movement of the connector part with respect to the emission part.

[0007] According to this disclosure, high transmission quality can be ensured.

[0008] This is a schematic diagram of a laser irradiation system equipped with a beam coupler according to the first embodiment of this disclosure. This is a schematic diagram of the beam coupler according to the first embodiment of this disclosure. This is a partially enlarged view of section C shown in Figure 2. This is a cross-sectional view along the cutting line IV-IV shown in Figure 3. This is a diagram showing a state in which the position of the second focal point is shifted in Figure 3. This is a schematic diagram showing a modified example of the focusing optical system. This is a partially enlarged view of the beam coupler according to the second embodiment of this disclosure.

[0009] Hereinafter, beam couplers according to the first and second embodiments of this disclosure will be described with reference to the drawings.

[0010] [First Embodiment] As shown in Figure 1, the beam coupler 200 of this embodiment is a relay device for optically connecting an oscillator fiber F1 connected to a laser oscillator 100 and a transmission fiber F2 connected to a laser head 300.

[0011] The beam coupler 200, together with, for example, the laser oscillator 100 and the laser head 300, constitutes the laser irradiation system 1. The laser irradiation system 1 is a processing machine that requires laser fiber transmission, such as a laser cutting machine, a laser welding machine, or a laser surface treatment device.

[0012] The beam coupler 200 is connected to the laser oscillator 100 via an oscillator fiber F1 and to the laser head 300 via a transmission fiber F2.

[0013] The laser oscillator 100 is a device that outputs laser light L. The laser oscillator 100 is a high-power type capable of outputting, for example, laser light L of about 10 kW. The laser head 300 is a device that irradiates with laser light L. If the laser irradiation system 1 is a laser processing machine, the laser head 300 is the processing head.

[0014] As shown in Figure 2, the beam coupler 200 includes an optical system housing section 210, an inlet section 220, an outlet section 230, an elliptical mirror 241, an inlet-side connector section 250, an outlet-side connector section 260, and a bellows 280.

[0015] The optical system housing 210 houses an elliptical mirror 241 which serves as a light-gathering optical system. The elliptical mirror 241 is, for example, a water-cooled elliptical copper mirror. An inlet section 220 and an outlet section 230 are connected to the optical system housing 210.

[0016] The incident section 220 is the portion into which the laser light L emitted from the end face of the oscillator fiber F1 is incident. The incident section 220 is connected to the incident-side connector section 250 which holds the end of the oscillator fiber F1. At this time, the position of the first focal point P1 of the elliptical mirror 241 is approximately the same as the position of the core exposed on the end face of the oscillator fiber F1. The laser light L incident from the incident section 220 travels while spreading out with a predetermined divergence angle and eventually reaches the elliptical mirror 241. The laser light L that reaches the elliptical mirror 241 is reflected by the elliptical mirror 241 and travels while converging towards the second focal point P2 of the elliptical mirror 241. The incident section 220 is provided with a cooling section (not shown) to suppress the temperature rise of the incident section 220.

[0017] The emission section 230 is the part from which the laser beam L, which propagates while being reflected and focused by the elliptical mirror 241, is emitted. The emission section 230 is connected to an emission-side connector section 260 that holds the end of the transmission fiber F2. At this time, the position of the second focal point P2 of the elliptical mirror 241 is approximately the same as the position of the core exposed on the end face of the transmission fiber F2. The emission section 230 is provided with a cooling section (not shown) to suppress the temperature rise of the emission section 230. The emission section 230 is made of metal, for example. When the emission section 230 is made of metal, the cooling effect of the cooling section is improved. Also, when the emission section 230 is made of metal, a heat dissipation effect from the metal itself can be expected.

[0018] As shown in Figure 3, the output section 230 includes a cylindrical portion 231 centered on the axis X1. The end face of the cylindrical portion 231 is an opening (output opening 232), and the laser light L reflected by the elliptical mirror 241 is configured to reach the output-side connector section 260 through the output opening 232. The axis X1 extends along the direction of propagation of the laser light L reflected by the elliptical mirror 241.

[0019] The output-side connector section 260 is positioned opposite the output section 230 in the direction of laser beam L propagation. The output-side connector section 260 has a connector body 261 and a mounting section 262. The connector body 261 and the mounting section 262 may be made of separate parts or may be made integrally from a single part. The output-side connector section 260 is made of metal, for example. If the output-side connector section 260 is made of metal, a heat dissipation effect due to the metal itself can be expected.

[0020] The connector body 261 is a cylindrical component centered on an axis X2 and holds the transmission fiber F2. The connector body 261 has a through hole 261a extending along the axis X2, and the laser beam L reaches the end face of the held transmission fiber F2 through the through hole 261a. The axis X2 extends along the direction of propagation of the laser beam L reflected by the elliptical mirror 241.

[0021] The mounting portion 262 is a cylindrical part centered on the axis X2 and is attached to the outer surface of the connector body 261.

[0022] A gap is formed between the emission section 230 and the emission-side connector section 260 (mounting section 262) in the direction of propagation of the laser light L reflected by the elliptical mirror 241. A bellows 280, acting as a cover, is provided between the emission section 230 and the emission-side connector section 260 (mounting section 262) to cover this gap.

[0023] The bellows 280 is a cylindrical component through which axis X1 (and / or axis X2) passes. The bellows 280 is deformable in a direction along axis X1 (and / or axis X2) and in a direction perpendicular to axis X1 (and / or axis X2). However, the bellows 280 only needs to be deformable to the extent that it allows movement of the ejection-side connector portion 260, which will be described later. The deformable bellows 280 is formed from a material with excellent flexibility. Examples of flexible materials include resin and rubber. One end of the bellows 280 is connected to the cylindrical portion 231 of the ejection portion 230. Specifically, one end of the bellows 280 is attached so as to tighten the outer circumferential surface of the cylindrical portion 231 of the ejection portion 230. The tightening is performed by a fastening device 281, such as a hose clamp (see Figure 4). On the other hand, the other end of the bellows 280 is connected to the mounting portion 262. Specifically, the other end of the bellows 280 is attached to tighten against the outer surface of the mounting portion 262. The tightening is performed by a fastening device 282, such as a hose clamp. By providing the bellows 280 in this way, the gap between the outlet portion 230 and the outlet-side connector portion 260 is covered by the bellows 280 around the axis X1 (and / or axis X2), and is isolated from the surroundings while ensuring airtightness.

[0024] As shown in Figure 2, the position of the core exposed on the end face of the transmission fiber F2 held in the output-side connector 260 is normally designed to coincide approximately with the position of the second focal point P2 where the laser light L reflected by the elliptical mirror 241 converges. However, due to the effects of slight thermal deformation of the elliptical mirror 241 caused by the high-power laser light L and manufacturing errors in the oscillator fiber F1, the position of the second focal point P2 may shift from the position of the core exposed on the end face of the transmission fiber F2, as shown in Figure 5. To address this, as shown in Figure 2, the beam coupler 200 is equipped with a position adjustment unit 270.

[0025] The position adjustment unit 270 is a mechanism for adjusting the position of the output-side connector unit 260. The position adjustment unit 270 is, for example, a three-axis stage supporting the output-side connector unit 260. The "three axes" here refer to, for example, a first axis along axis X1 (and / or axis X2), a second axis perpendicular to the first axis, and a third axis perpendicular to the first and second axes. In Figure 2, the first axis is an axis extending in the left-right direction, the second axis is an axis extending in the up-down direction, and the third axis is an axis extending in the depth direction. As a result, even if the second focal point P2 deviates from the position assumed in the design, the position of the core exposed from the end face of the transmission fiber F2 can be moved to the second focal point P2 by adjusting the position of the output-side connector unit 260. The position adjustment unit 270 is automatically controlled, for example, based on the amount of deviation of the second focal point P2 detected by a device (not shown).

[0026] When the position of the output-side connector section 260 is adjusted by the position adjustment section 270, the output-side connector section 260 moves relative to the output section 230. At this time, since the bellows 280 connected to the output section 230 and the output-side connector section 260 are deformable, the bellows 280 deforms to follow the movement of the output-side connector section 260. Therefore, when moving the transmission fiber F2 to the focal point, the bellows 280 does not hinder the movement of the output-side connector section 260.

[0027] [Modification 1] The cover portion that covers the gap between the ejection portion 230 and the ejection-side connector portion 260 is not limited to a bellows 280. Also, the cover portion does not have to be configured to be deformable as a whole, like the bellows 280, and it is sufficient if it includes at least a part that is deformable.

[0028] [Modification 2] As shown in Figure 6, the focusing optical system installed between the oscillator fiber F1 and the transmission fiber F2 to focus the laser light L may be a device having at least one lens 242. When a device having at least one lens 242 is used as the focusing optical system, the shift in the second focal point P2 may also occur due to the thermal lensing effect.

[0029] [Effect] Since the device is equipped with a position adjustment unit 270 for adjusting the position of the output-side connector unit 260, even if the second focal point P2 of the laser beam L deviates from the position assumed in the design, the transmission fiber F2 (core of the transmission fiber F2) can be moved to the second focal point P2 by adjusting the position of the output-side connector unit 260. This prevents burnout of the transmission fiber F2 and ensures high transmission quality.

[0030] Furthermore, since the device is equipped with a bellows 280 connected to the output section 230 and the output-side connector section 260, and covering the gap between the output section 230 and the output-side connector section 260, the possibility of foreign matter entering the gap from the outside is reduced. This ensures high transmission quality over a long period of time. At this time, the bellows 280 is deformable to allow the output-side connector section 260 to move relative to the output section 230, so when the output-side connector section 260 is moved, the bellows 280 deforms to follow it. Therefore, when moving the transmission fiber F2 to the second focal point P2, the bellows 280 does not hinder the movement of the output-side connector section 260.

[0031] [Second Embodiment] The beam coupler of this embodiment differs from the beam coupler of the first embodiment in that it is equipped with an output-side extension 291 and a connector-side extension 295, but is otherwise identical. Therefore, identical components are denoted by the same reference numerals and their descriptions are omitted.

[0032] As shown in Figure 7, an ejection-side extension 291 is provided at the end of the ejection section 230. The ejection section 230 and the ejection-side extension 291 may be made of separate parts or they may be made integrally as a single part. The ejection-side extension 291 may be made of metal, for example. If the ejection-side extension 291 is made of metal, a heat dissipation effect due to the metal itself can be expected.

[0033] The output-side extension 291 has an output-side cylindrical portion 292 and an output-side clamping portion 293. The output-side cylindrical portion 292 is a cylindrical part centered on the axis X1 and protrudes from the cylindrical portion 231 of the output section 230 in the direction of laser beam L propagation. However, the output-side cylindrical portion 292 does not come into contact with the output-side connector portion 260. The output-side clamping portion 293 is a cylindrical part centered on the axis X1 and having a larger diameter than the output-side cylindrical portion 292, and protrudes in the direction of laser beam L propagation. The output-side clamping portion 293 is a portion for attaching one end of the bellows 280.

[0034] A connector-side extension 295 is provided on the outer circumferential surface of the mounting portion 262 of the output-side connector portion 260. The mounting portion 262 and the connector-side extension 295 may be composed of separate parts or may be integrally composed of a single part. The connector-side extension 295 is made of metal, for example. If the connector-side extension 295 is made of metal, a heat dissipation effect due to the metal itself can be expected.

[0035] The connector-side extension 295 has a connector-side cylindrical portion 296 and a connector-side tightening portion 297. The connector-side cylindrical portion 296 is a cylindrical part centered on the axis X2 and protrudes from the mounting portion 262 in the direction opposite to the direction of travel of the laser beam L. However, the connector-side cylindrical portion 296 is not in contact with the emission portion 230. The connector-side tightening portion 297 is a cylindrical part centered on the axis X2 and having a larger diameter than the connector-side cylindrical portion 296, and protrudes in the direction opposite to the direction of travel of the laser beam L. The connector-side tightening portion 297 is a portion for attaching the other end of the bellows 280.

[0036] The ejection-side cylindrical portion 292 overlaps with the connector-side cylindrical portion 296 in the direction of axis X1 (and / or axis X2). In Figure 7, the length of the overlapping area in the direction of axis X1 (and / or axis X2) is denoted by "D". D is, for example, 2 mm or more and 10 mm or less. In addition, the ejection-side cylindrical portion 292 forms a gap between itself and the connector-side cylindrical portion 296 in the direction perpendicular to axis X1 (and / or axis X2). In the case of Figure 7, this gap is secured by making the outer diameter of the ejection-side cylindrical portion 292 smaller than the inner diameter of the connector-side cylindrical portion 296. By securing this gap, contact between the ejection-side cylindrical portion 292 and the connector-side cylindrical portion 296 is avoided when the ejection-side connector portion 260 is moved by the position adjustment unit 270. Therefore, when moving the transmission fiber F2 to the second focal point P2, the units of the output-side cylindrical portion 292 and the connector-side cylindrical portion 296 do not obstruct the movement of the output-side connector portion 260.

[0037] The ejection-side clamping portion 293 has a larger diameter than the ejection-side cylindrical portion 292, and the connector-side clamping portion 297 has a larger diameter than the connector-side cylindrical portion 296. Therefore, the bellows 280 attached to the ejection-side clamping portion 293 and the connector-side clamping portion 297 are located on the outside (outer circumference) of the ejection-side cylindrical portion 292 and the connector-side cylindrical portion 296 unit. In other words, the bellows 280 covers the ejection-side cylindrical portion 292 and the connector-side cylindrical portion 296 unit around axis X1 (and / or axis X2). Considering that the bellows 280 is cylindrical, it is preferable that the outer diameters of the ejection-side clamping portion 293 and the connector-side clamping portion 297 are approximately the same.

[0038] [Effect] The bellows 280 is located outside the output-side cylindrical portion 292 and the connector-side cylindrical portion 296. The output-side cylindrical portion 292 overlaps with the connector-side cylindrical portion 296 in the direction of axis X1 (and / or axis X2). Therefore, even if a portion of the laser beam L is reflected by the output-side connector portion 260, the reflected laser beam L (shown as a dashed line in Figure 7) is blocked by the output-side cylindrical portion 292 and / or the connector-side cylindrical portion 296 and does not reach the bellows 280. This prevents damage to the bellows 280 from the laser beam L. Also, since the laser beam L does not reach the bellows 280, it is not necessary to give the material of the bellows 280 sufficient performance to withstand the laser beam L, thus increasing the range of materials that can be used for the bellows 280. This allows, for example, easy-to-handle materials and readily available general materials to be used as the material for the bellows 280. Furthermore, if the output-side cylindrical portion 292 and / or the connector-side cylindrical portion 296 are made of metal, even if reflected laser light L is irradiated onto the output-side cylindrical portion 292 and / or the connector-side cylindrical portion 296, they are less likely to be damaged by the laser light L, and cooling is promoted by the heat dissipation effect of the metal itself.

[0039] [Modification 3] As described above, in order to overlap the ejection-side cylindrical portion 292 with the connector-side cylindrical portion 296 in the direction of axis X1 (and / or axis X2), and to form a gap between the ejection-side cylindrical portion 292 and the connector-side cylindrical portion 296 in the direction perpendicular to axis X1 (and / or axis X2), the outer diameter of the ejection-side cylindrical portion 292 was made smaller than the inner diameter of the connector-side cylindrical portion 296, and the ejection-side cylindrical portion 292 was inserted inside the connector-side cylindrical portion 296. However, the outer diameter of the connector-side cylindrical portion 296 may be made smaller than the inner diameter of the ejection-side cylindrical portion 292, and the connector-side cylindrical portion 296 may be inserted inside the ejection-side cylindrical portion 292.

[0040] However, when the output-side cylindrical portion 292 is inserted inside the connector-side cylindrical portion 296, the following effect may occur. That is, the laser light L (shown as a dashed line in Figure 7) reflected by the output-side connector portion 260 is first irradiated onto the output-side cylindrical portion 292. At this time, since the output portion 230 on which the output-side cylindrical portion 292 is provided is equipped with a cooling section (not shown), the output-side cylindrical portion 292 is also actively cooled, and the temperature rise of the output-side cylindrical portion 292 due to irradiation by the reflected laser light L can be prevented.

[0041] [Note] The beam coupler of this embodiment, as described above, can be understood, for example, as follows.

[0042] A beam coupler (200) according to a first aspect of the present disclosure includes an emission section (230) from which focused laser light (L) is emitted toward a transmission fiber (F2), a connector section (260) facing the emission section in the direction of propagation of the laser light and holding the transmission fiber into which the laser light is incident, a position adjustment section (270) for adjusting the position of the connector section, and a cover section (280) connected to the emission section and the connector section and covering the gap between the emission section and the connector section, wherein the cover section is deformable to allow movement of the connector section relative to the emission section.

[0043] Since it has a position adjustment part for adjusting the position of the connector part, even if the focus of the laser beam deviates from the position assumed in the design, by adjusting the position of the connector part, the transmission fiber (the core of the transmission fiber) can be moved to the focus. Thereby, it is possible to prevent burning of the transmission fiber and ensure high transmission quality. Also, since it has a cover part that is connected to the emission part and the connector part and covers the gap between the emission part and the connector part, the possibility of foreign matter entering the gap from the outside is reduced. Thereby, high transmission quality can be ensured over a long period. At this time, since the cover part is deformable so as to allow movement of the connector part with respect to the emission part, when the connector part is moved, the cover part deforms so as to follow it. Therefore, when moving the transmission fiber to the focus, the cover part does not interfere with the movement of the connector part.

[0044] In the beam coupler according to the second aspect of the present disclosure, in the first aspect, the cover part is a bellows (280) having a cylindrical shape through which an axis (X1, X2) along the traveling direction passes through the inside.

[0045] Since the cover part is a cylindrical bellows, deformation of the cover part can be easily realized.

[0046] In the beam coupler according to the third aspect of the present disclosure, in the second aspect, the emission part is provided with an emission-side cylindrical part (292) having a cylindrical shape centered on the axis and protruding in the traveling direction, and the connector part is provided with a connector-side cylindrical part (296) having a cylindrical shape centered on the axis and protruding in the opposite direction of the traveling direction. The cover part is located outside the emission-side cylindrical part and the connector-side cylindrical part, and the emission-side cylindrical part overlaps with the connector-side cylindrical part in the direction of the axis.

[0047] The cover part is located outside the emission-side cylindrical part and the connector-side cylindrical part, and the emission-side cylindrical part overlaps with the connector-side cylindrical part in the axial direction. Therefore, even if a part of the laser light is reflected by the connector part, the reflected laser light is blocked by the emission-side cylindrical part and / or the connector-side cylindrical part and does not reach the cover part. Thereby, damage to the cover part by the laser light can be prevented.

[0048] In the beam coupler according to the fourth aspect of the present disclosure, in the third aspect, a cooling part is provided in the emission part, and the emission-side cylindrical part is inserted inside the connector-side cylindrical part.

[0049] Since a cooling part is provided in the emission part, the temperature rise of the emission part can be suppressed. Also, since the emission-side cylindrical part is inserted inside the connector-side cylindrical part, the laser light reflected by the connector part is first irradiated onto the emission-side cylindrical part. At this time, since a cooling part is provided in the emission part where the emission-side cylindrical part is provided, the emission-side cylindrical part is also actively cooled, and the temperature rise of the emission-side cylindrical part due to the irradiation of the reflected laser light can be prevented.

[0050] The beam coupler according to the fifth aspect of the present disclosure includes a water-cooled elliptical copper mirror that condenses the laser light directed toward the transmission fiber in any one of the first aspect to the fourth aspect.

[0051] The beam coupler according to the sixth aspect of the present disclosure includes a condenser lens that condenses the laser light directed toward the transmission fiber in any one of the first aspect to the fourth aspect.

[0052] 1 Laser irradiation system 100 Laser oscillator 200 Beam coupler 210 Optical system housing 220 Incident section 230 Outlet section 231 Cylindrical section 232 Outlet aperture 241 Elliptical mirror 242 Lens 250 Incident side connector section 260 Outlet side connector section 261 Connector body 261a Through hole 262 Mounting section 270 Position adjustment section 280 Bellows 281 Fastener 282 Fastener 291 Outlet side extension section 292 Outlet side cylindrical section 293 Outlet side fastening section 295 Connector side extension section 296 Connector side cylindrical section 297 Connector side fastening section 300 Laser head F1 Oscillator fiber F2 Transmission fiber L Laser light

Claims

1. A beam coupler comprising: an emission section from which focused laser light is emitted toward a transmission fiber; a connector section facing the emission section in the direction of propagation of the laser light and holding the transmission fiber into which the laser light is incident; a position adjustment section for adjusting the position of the connector section; and a cover section connected to the emission section and the connector section and covering the gap between the emission section and the connector section, wherein the cover section is deformable to allow movement of the connector section relative to the emission section.

2. The beam coupler according to claim 1, wherein the cover portion is a cylindrical bellows with an axis along the direction of travel passing through the inside.

3. The beam coupler according to claim 2, wherein the ejection portion is provided with an ejection-side cylindrical portion that is cylindrical around the axis and protrudes toward the direction of travel, the connector portion is provided with a connector-side cylindrical portion that is cylindrical around the axis and protrudes toward the opposite direction of travel, the cover portion is located outside the ejection-side cylindrical portion and the connector-side cylindrical portion, and the ejection-side cylindrical portion overlaps with the connector-side cylindrical portion in the direction of the axis.

4. The beam coupler according to claim 3, wherein the discharge portion is provided with a cooling portion, and the discharge-side cylindrical portion is inserted inside the connector-side cylindrical portion.

5. The beam coupler according to any one of claims 1 to 4, comprising a water-cooled elliptical copper mirror for focusing laser light directed toward the transmission fiber.

6. The beam coupler according to any one of claims 1 to 4, further comprising a focusing lens for focusing laser light directed toward the transmission fiber.

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