Beam coupler

Abstract

We provide a beam coupler that can ensure high transmission quality. [Solution] The system includes an output section 230 from which focused laser light L is emitted toward a transmission fiber F2, an output-side connector section 260 facing the output section 230 in the direction of propagation of the laser light L and holding the transmission fiber F2 into which the laser light L is incident, a position adjustment section for adjusting the position of the output-side connector section 260, and a bellows 280 connected to the output section 230 and the output-side connector section 260, covering the gap between the output section 230 and the output-side connector section 260, wherein the bellows 280 is deformable to allow movement of the output-side connector section 260 relative to the output section 230.

Description

Technical Field

[0001] The present disclosure relates to a beam coupler.

Background Art

[0002] For example, Patent Document 1 discloses a fiber coupler that causes a beam emitted from a receiving fiber to enter a transmission fiber via 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.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[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 originally present inside the housing adheres to the receiving fiber, the focusing lens, or the transmission fiber, deteriorating the transmission quality.

[0005] The present 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.

Means for Solving the Problems

[0006] In order to solve the above problems, the beam coupler of the present disclosure employs the following means. A beam coupler according to one aspect of the present disclosure includes 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. [Effects of the Invention]

[0007] According to this disclosure, high transmission quality can be ensured. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of a laser irradiation system equipped with a beam coupler according to the first embodiment of this disclosure. [Figure 2] This is a schematic diagram of a beam coupler according to the first embodiment of this disclosure. [Figure 3] This is a magnified view of section C shown in Figure 2. [Figure 4] Figure 3 shows a cross-sectional view along the cutting line IV-IV. [Figure 5] Figure 3 shows the state where the position of the second focal point has shifted. [Figure 6] This is a schematic diagram showing a modified example of a light-gathering optical system. [Figure 7] This is a partially enlarged view of a beam coupler according to the second embodiment of this disclosure. [Modes for carrying out the invention]

[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 FIG. 1, the beam coupler 200 of the present embodiment is a relay device for optically connecting the oscillator fiber F1 connected to the laser oscillator 100 and the transmission fiber F2 connected to the laser head 300.

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

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

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

[0014] As shown in FIG. 2, the beam coupler 200 has an optical system housing portion 210, an incident portion 220, an exit portion 230, an elliptical mirror 241, an incident-side connector portion 250, an exit-side connector portion 260, and a bellows 280.

[0015] The optical system housing portion 210 houses the elliptical mirror 241 as a condensing optical system. The elliptical mirror 241 is, for example, a water-cooled elliptical copper mirror. The incident portion 220 and the exit portion 230 are connected to the optical system housing portion 210.

[0016] The incident portion 220 is a portion where the laser light L emitted from the end face of the oscillator fiber F1 is incident. The incident part 220 is connected to an incident-side connector part 250 that holds the end of the oscillator fiber F1. At this time, the position of the first focal point P1 of the elliptical mirror 241 substantially coincides with the position of the core exposed on the end face of the oscillator fiber F1. The laser beam L incident from the incident part 220 travels while spreading with a predetermined divergence angle and eventually reaches the elliptical mirror 241. The laser beam L that reaches the elliptical mirror 241 is reflected by the elliptical mirror 241 and travels while converging toward the second focal point P2 of the elliptical mirror 241. A cooling part (not shown) is provided in the incident part 220, suppressing the temperature rise of the incident part 220.

[0017] The emission part 230 is the part where the laser beam L that is reflected by the elliptical mirror 241 and travels while converging is emitted. The emission part 230 is connected to an emission-side connector part 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 substantially coincides with the position of the core exposed on the end face of the transmission fiber F2. A cooling part (not shown) is provided in the emission part 230, suppressing the temperature rise of the emission part 230. The emission part 230 is made of, for example, metal. When the emission part 230 is made of metal, the cooling effect by the cooling part is improved. Also, when the emission part 230 is made of metal, the heat dissipation effect by the metal itself can be expected.

[0018] As shown in FIG. 3, the emission part 230 includes a cylindrical part 231 centered on the axis X1. The end face of the cylindrical part 231 is an opening (emission opening 232), and is configured such that the laser beam L reflected by the elliptical mirror 241 reaches the emission-side connector part 260 through the emission opening 232. The axis X1 extends along the traveling direction of the laser beam L reflected by the elliptical mirror 241.

[0019] The emission-side connector part 260 is arranged facing the emission part 230 in the traveling direction of the laser beam L. The output-side connector portion 260 has a connector body 261 and a mounting portion 262. The connector body 261 and the mounting portion 262 may be made up of separate parts, or they may be made up as a single integrated part. The output-side connector portion 260 is made of metal, for example. When the output-side connector portion 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 the axis X2 and holds the transmission fiber F2. The connector body 261 has a through-hole 261a extending along the axis X2, and is configured so that the laser light L reaches the end face of the held transmission fiber F2 through the through-hole 261a. Furthermore, 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 axis X2 and is attached to the outer surface of the connector body 261.

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

[0023] The bellows 280 is a cylindrical component through which axis X1 (and / or axis X2) passes inside. 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 output-side connector portion 260, which will be described later. The deformable bellows 280 is formed from a highly flexible material. Examples of flexible materials include resin and rubber. One end of the bellows 280 is connected to the cylindrical portion 231 of the injection section 230. Specifically, one end of the bellows 280 is attached so as to tighten around the outer circumferential surface of the cylindrical portion 231 of the injection section 230. The tightening is performed by a clamping 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 so as to tighten around 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 ejection section 230 and the ejection-side connector section 260 is covered around the axis X1 (and / or axis X2) by the bellows 280, 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 portion 260 is typically 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 slight thermal deformation of the elliptical mirror 241 caused by the high-power laser beam L and the manufacturing errors of 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, the beam coupler 200 is equipped with a position adjustment unit 270, as shown in Figure 2.

[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 ejection-side connector unit 260. The "three axes" referred to here are, 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. This allows the position of the core exposed from the end face of the transmission fiber F2 to be moved to the second focal point P2, even if the second focal point P2 is shifted from the position assumed in the design, by adjusting the position of the output-side connector 260. The position adjustment unit 270 is automatically controlled based on the amount of displacement of the second focal point P2 detected by, for example, a device (not shown).

[0026] When the position of the ejection-side connector section 260 is adjusted by the position adjustment section 270, the ejection-side connector section 260 moves relative to the ejection section 230. In this case, the bellows 280 connected to the output section 230 and the output-side connector section 260 are deformable, 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 focal point, the bellows 280 does not hinder the movement of the output-side connector section 260.

[0027] [Example 1] The cover portion that covers the gap between the ejection portion 230 and the ejection-side connector portion 260 is not limited to the bellows 280. Furthermore, the cover portion does not need to be configured to be entirely deformable like the bellows 280; it is sufficient if it includes at least a portion that is deformable.

[0028] [Differentiation 2] As shown in Figure 6, the focusing optical system, which is 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. If a device with at least one lens 242 as a focusing optical system is employed, the shift in the second focal point P2 may also occur due to the thermal lensing effect.

[0029] [effect] Since the output-side connector section 260 is equipped with a position adjustment section 270 for adjusting its position, even if the second focal point P2 of the laser beam L deviates from the position assumed in the design, the transmission fiber F2 (the core of the transmission fiber F2) can be moved to the second focal point P2 by adjusting the position of the output-side connector section 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. In this case, 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 includes 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 composed of separate parts, or they may be integrally composed of a single part. The ejection-side extension 291 is made of metal, for example. When the ejection-side extension 291 is made of metal, a heat dissipation effect due to the metal itself can be expected.

[0033] The ejection-side extension 291 has an ejection-side cylindrical portion 292 and an ejection-side clamping portion 293 formed thereon. The discharge-side cylindrical portion 292 is a cylindrical part centered on the axis X1 and protrudes from the cylindrical portion 231 of the discharge section 230 in the direction of propagation of the laser beam L. However, the discharge-side cylindrical portion 292 is not in contact with the discharge-side connector section 260. The exit-side clamping portion 293 is a cylindrical portion centered on the axis X1 and having a larger diameter than the exit-side cylindrical portion 292, and protrudes in the direction of propagation of the laser beam L. The exit-side clamping portion 293 is the 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 they 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 propagation of the laser beam L. However, the connector-side cylindrical portion 296 is not in contact with the emission portion 230. The connector-side clamping portion 297 is a cylindrical portion 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 propagation of the laser beam L. The connector-side clamping portion 297 is the 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 to 10 mm. Furthermore, the output-side cylindrical portion 292 forms a gap between itself and the connector-side cylindrical portion 296 in a direction perpendicular to the axis X1 (and / or axis X2). In the case of Figure 7, this gap is secured by making the outer diameter of the output-side cylindrical portion 292 smaller than the inner diameter of the connector-side cylindrical portion 296. By securing this gap, contact between the output-side cylindrical portion 292 and the connector-side cylindrical portion 296 is avoided when the output-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 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] Since 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, the bellows 280 attached to the ejection-side clamping portion 293 and the connector-side clamping portion 297 will be 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 will cover the ejection-side cylindrical portion 292 and the connector-side cylindrical portion 296 unit around axis X1 (and / or axis X2). Furthermore, considering that the bellows 280 has a cylindrical shape, it is preferable that the outer diameter of the discharge-side tightening portion 293 and the outer diameter of the connector-side tightening portion 297 be 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. Furthermore, since the laser beam L does not reach the bellows 280, it is no longer necessary to give the material of the bellows 280 the performance required to withstand the laser beam L, thus increasing the range of material options for the bellows 280. This allows for the use of materials that are easy to handle or readily available and common materials 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] [Difference 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 smaller than the inner diameter of the discharge-side cylindrical portion 292, and the connector-side cylindrical portion 296 may be inserted inside the discharge-side cylindrical portion 292.

[0040] However, if the ejection-side cylindrical portion 292 is inserted inside the connector-side cylindrical portion 296, the following effects may occur. In other words, 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, thereby preventing a temperature rise in the output-side cylindrical portion 292 due to irradiation by the reflected laser light L.

[0041] [Note] As described above, the beam coupler of this embodiment 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] Because it is equipped with a position adjustment mechanism for adjusting the position of the connector, even if the focal point of the laser beam deviates from the position intended in the design, the transmission fiber (the core of the transmission fiber) can be moved to the focal point by adjusting the position of the connector. This prevents burnout of the transmission fiber and ensures high transmission quality. Furthermore, since it is equipped with a cover portion that is connected to the output portion and the connector portion and covers the gap between the output portion and the connector portion, 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 cover portion is deformable to allow the connector portion to move relative to the output portion, so when the connector portion is moved, the cover portion deforms to follow it. Therefore, when moving the transmission fiber to the focal point, the cover portion does not hinder the movement of the connector portion.

[0044] In the beam coupler according to a second aspect of the present disclosure, in the first aspect, the cover portion is a cylindrical bellows (280) through which axes (X1, X2) along the direction of travel pass on the inside.

[0045] Since the cover is made of a cylindrical bellows, the cover can be easily deformed.

[0046] In the beam coupler according to a third aspect of the present disclosure, in the second aspect, the output portion is provided with an output-side cylindrical portion (292) that is cylindrical around the axis and protrudes toward the direction of travel, and the connector portion is provided with a connector-side cylindrical portion (296) that is cylindrical around the axis and protrudes toward the opposite direction of travel, and the cover portion is located outside the output-side cylindrical portion and the connector-side cylindrical portion, and the output-side cylindrical portion overlaps with the connector-side cylindrical portion in the direction of the axis.

[0047] The cover is located outside the output-side cylindrical portion and the connector-side cylindrical portion, and the output-side cylindrical portion overlaps with the connector-side cylindrical portion in the axial direction. Therefore, even if some of the laser light is reflected by the connector portion, the reflected laser light is blocked by the output-side cylindrical portion and / or the connector-side cylindrical portion and does not reach the cover portion. This prevents damage to the cover portion by the laser light.

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

[0049] Since a cooling section is provided in the injection section, the temperature rise of the injection section can be suppressed. Furthermore, since the discharge-side cylindrical portion is inserted inside the connector-side cylindrical portion, the laser light reflected from the connector portion is first irradiated onto the discharge-side cylindrical portion. At this time, since the discharge section where the discharge-side cylindrical portion is provided is equipped with a cooling section, the discharge-side cylindrical portion is also actively cooled, preventing a temperature rise in the discharge-side cylindrical portion due to irradiation with reflected laser light.

[0050] A beam coupler according to a fifth aspect of this disclosure, in any of the first to fourth aspects, includes a water-cooled elliptical copper mirror for focusing laser light directed toward the transmission fiber.

[0051] A beam coupler according to a sixth aspect of this disclosure, in any of the first to fourth aspects, includes a focusing lens for focusing laser light directed toward the transmission fiber. [Explanation of symbols]

[0052] 1. Laser irradiation system 100 Laser Oscillators 200 Beam Coupler 210 Optical System Housing 220 Input part 230 Ejection section 231 Cylindrical part 232 Ejection aperture 241 Elliptical Mirror 242 lenses 250 Inlet side connector section 260 Outlet side connector section 261 Connector body 261a Through hole 262 Mounting parts 270 Position adjustment section 280 Bellows 281 Fasteners 282 Fasteners 291 Output side extension 292 Output side cylindrical part 293 Outlet side clamping part 295 Connector-side extension 296 Connector side cylindrical part 297 Connector side tightening part 300 laser heads F1 Oscillator Fiber F2 transmission fiber L laser light

Claims

1. An emission section from which focused laser light is emitted toward the transmission fiber, A connector portion facing the output portion in the direction of laser beam propagation and holding the transmission fiber into which the laser beam is incident, A position adjustment unit for adjusting the position of the connector portion, A cover portion connected to the ejection portion and the connector portion, covering the gap between the ejection portion and the connector portion, Equipped with, The cover portion is deformable to allow movement of the connector portion relative to the ejection portion. Beam coupler.

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

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

4. The injection unit is provided with a cooling unit. The ejection-side cylindrical portion is inserted inside the connector-side cylindrical portion. The beam coupler according to claim 3.

5. It is equipped with a water-cooled elliptical copper mirror that focuses the laser light directed toward the transmission fiber. A beam coupler according to any one of claims 1 to 4.

6. It is equipped with a focusing lens that focuses the laser light directed toward the transmission fiber. A beam coupler according to any one of claims 1 to 4.

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