Laser processing equipment
The laser processing apparatus addresses the issue of laser oscillator damage by implementing a return light detection mechanism with sensors and power reduction units, ensuring effective management and reduction of reflected light intensity, thereby enhancing safety and reliability.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- FURUKAWA ELECTRIC CO LTD
- Filing Date
- 2022-03-28
- Publication Date
- 2026-06-19
AI Technical Summary
Conventional laser processing apparatuses struggle to reliably suppress damage to the laser oscillator due to return light, as there is a delay in temperature rise detection, leading to potential damage.
The apparatus incorporates a return light detection mechanism with sensors and power reduction units, including absorption, leakage, and cooling mechanisms to manage and reduce the intensity of reflected light, utilizing optical fibers and controllers to control laser output based on detected light intensity.
This configuration effectively suppresses damage to the laser oscillator by reliably managing and reducing the power of return light, enhancing the apparatus's operational safety and reliability.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a laser processing apparatus.
Background Art
[0002] Conventionally, as a laser processing apparatus that irradiates a processing target with laser light output from a laser oscillator for processing, there is known a laser processing apparatus provided with an attenuation unit that attenuates the return light from the processing target or the like to the laser oscillator, and stops the output of the laser light by the laser oscillator according to the temperature rise in the attenuation unit (for example, Patent Document 1). Thereby, damage to the laser oscillator due to the return light can be suppressed.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] In the configuration of Patent Document 1, if it takes time from when the intensity of the return light increases due to some cause until the temperature of the attenuator rises, it may be difficult to suppress damage to the laser oscillator due to the return light.
[0005] Therefore, one of the problems of the present invention is to obtain an improved and novel laser processing apparatus that can more reliably suppress damage to the laser oscillator due to, for example, return light.
Means for Solving the Problems
[0006] The laser processing apparatus of the present invention comprises, for example, a light-emitting device that outputs laser light, a first optical fiber that transmits the laser light output from the light-emitting device, an optical head that emits the laser light transmitted by the first optical fiber toward a workpiece, a second optical fiber that transmits the reflected light from the optical head, and a first sensor that detects the leaked light of the reflected light that leaks from the outer circumference of the second optical fiber.
[0007] The laser processing apparatus may also include a second sensor provided on the side of the second optical fiber opposite to the optical head for detecting the reflected light output from the second optical fiber, and a power reduction unit for reducing the power of the reflected light input to the second sensor.
[0008] The laser processing apparatus may include a controller that controls the operation of the light-emitting device based on at least one of the detection signals from the first sensor and the detection signals from the second sensor.
[0009] In the laser processing apparatus, the second sensor may detect the intensity distribution of the reflected light.
[0010] The laser processing apparatus comprises a plurality of light-emitting devices as the light-emitting devices, a plurality of first optical fibers as the first optical fibers, each transmitting the laser light from the light-emitting devices, a multiplexing unit that combines the laser light transmitted by the plurality of first optical fibers from the plurality of light-emitting devices, and a third optical fiber that transmits the laser light combined in the multiplexing unit to the optical head, wherein the second optical fiber may be optically connected to the multiplexing unit on the side opposite to the third optical fiber with respect to the multiplexing unit.
[0011] Furthermore, the laser processing apparatus of the present invention includes, for example, a light-emitting device that outputs laser light, a first optical fiber that transmits the laser light output from the light-emitting device, an optical head that emits the laser light transmitted by the first optical fiber toward a workpiece, a second optical fiber that transmits the reflected light from the optical head, a second sensor provided on the side of the second optical fiber opposite to the optical head for detecting the reflected light output from the second optical fiber, and a power reduction unit that reduces the power of the reflected light input to the second sensor.
[0012] In the laser processing apparatus, the power reduction unit may have an absorption unit that absorbs the reflected light.
[0013] In the laser processing apparatus, the absorption section may have a body with holes into which the reflected light is introduced.
[0014] In the laser processing apparatus, an uneven structure may be provided on the inner circumferential surface of the hole.
[0015] In the laser processing apparatus, the inner circumferential surface of the hole may have a tapered shape in which the inner diameter narrows as it approaches the direction in which the reflected light enters the hole.
[0016] In the laser processing apparatus, the absorption portion may have an absorption layer provided on the inner circumferential surface of the hole that absorbs the reflected light.
[0017] The laser processing apparatus includes, as the second optical fiber, a fourth optical fiber and a fifth optical fiber provided with a gap between them, to which the reflected light output from the fourth optical fiber is coupled, and the body may support the fourth optical fiber and the fifth optical fiber spaced apart in the direction of the optical axis of the reflected light in the hole.
[0018] The laser processing apparatus may be thermally connected to the body and include a cooling mechanism for cooling the body.
[0019] The laser processing apparatus may include a light shielding portion that partially shields the return light as the power reduction portion.
[0020] The laser processing apparatus may include a filter that attenuates the return light as the power reduction portion.
[0021] The laser processing apparatus may include an expander that expands the width of the beam of the return light as the power reduction portion.
[0022] In the laser processing apparatus, the power reduction portion may have a leakage portion that leaks the return light.
[0023] The laser processing apparatus includes a fourth optical fiber as the second optical fiber, and a fifth optical fiber provided with a gap from the fourth optical fiber and to which the return light output from the fourth optical fiber is coupled. The power reduction portion may have a first leakage portion where the return light leaks from the gap as the leakage portion.
[0024] In the laser processing apparatus, the optical axis of the fourth optical fiber and the optical axis of the fifth optical fiber may be displaced from each other.
[0025] In the laser processing apparatus, the second optical fiber has a sixth optical fiber having a curved portion, and the power reduction portion may have a second leakage portion where the return light leaks from the curved portion as the leakage portion.
[0026] The laser processing apparatus includes a plurality of light emitting devices as the light emitting device, a plurality of first optical fibers as the first optical fiber, the plurality of first optical fibers each transmitting the laser light from the light emitting device, a multiplexing portion that multiplexes the laser light from the plurality of light emitting devices transmitted by the plurality of first optical fibers, and a third optical fiber that transmits the laser light multiplexed by the multiplexing portion to the optical head. The second optical fiber may be optically connected to the multiplexing portion on the side opposite to the third optical fiber with respect to the multiplexing portion. [Effect of the Invention]
[0027] According to the present invention, for example, it is possible to obtain a novel and improved laser processing apparatus that can more reliably suppress damage to a laser oscillator caused by return light. [Brief Description of the Drawings]
[0028] [Figure 1] FIG. 1 is an exemplary schematic diagram of a laser processing apparatus according to the first embodiment. [Figure 2] FIG. 2 is an exemplary and schematic side view (partial cross-sectional view) of the return light detection mechanism according to the first embodiment. [Figure 3] FIG. 3 is an exemplary and schematic side view (partial cross-sectional view) of the return light detection mechanism according to the second embodiment. [Figure 4] FIG. 4 is an exemplary and schematic side view (partial cross-sectional view) of the return light detection mechanism according to the third embodiment. [Figure 5] FIG. 5 is an exemplary and schematic cross-sectional view of the power reduction unit according to the fourth embodiment. [Figure 6] FIG. 6 is an exemplary and schematic cross-sectional view of the power reduction unit according to the fifth embodiment. [Figure 7] FIG. 7 is an exemplary and schematic cross-sectional view of the power reduction unit according to the sixth embodiment. [Figure 8] FIG. 8 is an exemplary and schematic cross-sectional view of the power reduction unit according to the seventh embodiment. [Figure 9] FIG. 9 is an exemplary and schematic cross-sectional view of the power reduction unit according to the eighth embodiment. [Figure 10] FIG. 10 is an exemplary and schematic cross-sectional view of the power reduction unit according to the ninth embodiment. [Figure 11] FIG. 11 is an exemplary and schematic cross-sectional view of the power reduction unit according to the tenth embodiment. [Figure 12] FIG. 12 is an exemplary and schematic side view of the return light detection mechanism according to the eleventh embodiment. [Figure 13]Figure 13 is an exemplary and schematic side view of the return light detection mechanism of the twelfth embodiment. [Figure 14] Figure 14 is an exemplary and schematic side view of the return light detection mechanism of the 13th embodiment. [Figure 15] Figure 15 is an illustrative schematic diagram of a laser processing apparatus according to the 14th embodiment. [Modes for carrying out the invention]
[0029] Illustrative embodiments of the present invention are disclosed below. The configurations of the embodiments shown below, as well as the actions and results (effects) brought about by such configurations, are examples only. The present invention can also be realized by configurations other than those disclosed in the following embodiments. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derived effects) that can be obtained by the configuration.
[0030] The multiple embodiments shown below have similar configurations. Therefore, the configuration of each embodiment yields similar functions and effects based on the same configuration. In addition, the same reference numerals are used for these similar configurations below, and redundant explanations may be omitted.
[0031] In this specification, ordinal numbers are assigned for convenience to distinguish parts, components, etc., and do not indicate priority or order.
[0032] [First Embodiment] [Configuration of the laser processing machine] Figure 1 is a schematic diagram of the laser processing apparatus 100A(100) of the embodiment. The laser processing apparatus 100 comprises a plurality of light-emitting devices 111, a plurality of optical fibers 12, a coupler 10, a single optical fiber 13, an optical head 120A(120), and a controller 200.
[0033] Each light-emitting device 111 is a laser device that outputs laser light. For example, each light-emitting device 111 outputs laser light with a wavelength of 400 nm to 550 nm. Note that each light-emitting device 111 may output laser light of different wavelengths.
[0034] The optical fiber 11 transmits the laser light output from each of the light-emitting devices 111. The optical fiber 11 is, for example, a multimode optical fiber. The optical fiber 11 is an example of a first optical fiber.
[0035] The coupler 10 is optically connected to multiple optical fibers 11 and combines the laser light from the multiple optical fibers 11. The coupler 10 is, for example, a TFB (tapered fiber bundle). The coupler 10 is an example of a multiplexing unit.
[0036] The optical fiber 13 is optically connected to the coupler 10 and transmits the laser light combined by the coupler 10. The optical fiber 13 is, for example, a multimode optical fiber. The optical fiber 13 is an example of a third optical fiber.
[0037] The optical head 120 receives laser light via multiple optical fibers 11, a coupler 10, and an optical fiber 13. The optical head 120 transmits the laser light internally and irradiates the surface of the workpiece W with focused laser light L. By irradiating the workpiece W with laser light L, the optical head 120 performs laser processing on the workpiece W, such as laser welding or laser cutting.
[0038] The laser processing apparatus 100 may include a relative movement mechanism (not shown) that moves the optical head 120 and the workpiece W in a direction intersecting the optical axis (irradiation direction) of the laser beam L so that the laser beam L is scanned on the surface Wa. The laser processing apparatus 100 may also include a galvanometer scanner (not shown) that changes the emission direction of the laser beam L from the optical head 120 so that the laser beam L is scanned on the surface Wa. In this case, the galvanometer scanner is provided on the optical head 120. The laser processing apparatus 100 may also include both the relative movement mechanism and the galvanometer scanner.
[0039] The controller 200 is a circuit that operates as a computer and outputs an operation control signal that switches the operation of the light-emitting device 111 on and off. In other words, the operation of the light-emitting device 111 is controlled by the controller 200.
[0040] [Optical head configuration] The optical head 120 includes a collimating lens 121 and a focusing lens 122. The collimating lens 121 and the focusing lens 122 may also be referred to as optical components. The optical components of the optical head 120 may be changed depending on the wavelength of the laser light, etc.
[0041] The collimating lens 121 collimates the laser light input from the optical fiber 13. The collimated laser light becomes parallel light.
[0042] The focusing lens 122 focuses the laser light from the collimating lens 121 as parallel light and directs the laser light L (output light) toward the surface Wa of the workpiece W. If the optical head 120 has a galvanometer scanner, the galvanometer scanner is provided, for example, between the collimating lens 121 and the focusing lens 122.
[0043] [Detection of reflected light] When the reflected light of the laser beam L from the workpiece W is re-input to the optical head 120 and returns to the light-emitting device 111 via the optical head 120, optical fiber 13, coupler 10, and optical fiber 11, there is a risk that the light-emitting device 111 may be damaged. Therefore, the laser processing apparatus 100 is equipped with a reflected light detection mechanism 130 that detects the reflected light from the optical head 120.
[0044] The return light detection mechanism 130 is optically connected to the coupler 10 via the optical fiber 12. The optical fiber 12 is optically connected to the coupler 10 on the opposite side from the optical fiber 13. When return light from the optical head 120 is transmitted in the optical fiber 13, a portion of it is coupled to the optical fiber 12 via the coupler 10 at a predetermined branching ratio. The optical fiber 12 transmits the return light from the coupler 10 to the return light detection mechanism 130. The optical fiber 12 is an example of a second optical fiber.
[0045] Figure 2 is a side view (partial cross-sectional view) of the return light detection mechanism 130A(130) of this embodiment. The return light detection mechanism 130A(130) includes a power reduction unit 131A(131), a connector 132, a heat sink 131b, and a sensor 141.
[0046] Sensor 141 detects the leaked light Lr of the return light that leaks from the outer circumference of the optical fiber 12. Sensor 141 may be provided with a gap between it and the outer circumference of the optical fiber 12, or it may be provided in contact with the outer circumference. In addition, the outer sheath of the optical fiber 12 may be partially removed in the portion of the optical fiber 12 that faces sensor 141. Sensor 141 is an example of a first sensor.
[0047] The controller 200 (see Figure 1) controls the operation of the light-emitting device 111 based on the detection signal from the sensor 141. For example, the controller 200 may stop the output of the light-emitting device 111 if the intensity of the detection signal is above a predetermined threshold. Alternatively, the controller 200 may control the operation of the light-emitting device 111 such that the output of the laser light from the light-emitting device 111 decreases as the intensity of the detection signal increases.
[0048] The power reduction unit 131 reduces the intensity of the reflected light Lr. In this embodiment, the power reduction unit 1313 has a body 131a as an absorbing unit that absorbs the reflected light Lr.
[0049] The body 131a is provided with a hole 131a1 into which the reflected light Lr is introduced. The hole 131a1 has, for example, a bottomed cylindrical shape. A connector 132, which is optically connected to the optical fiber 12, is attached to the open end of the hole 131a1. In this configuration, the reflected light Lr is introduced into the hole 131a1 from the optical fiber 12 via the connector 132. The connector 132 is coated with an anti-reflective coating. The central axis of the hole 131a1 and the optical axis direction of the connector 132 are approximately coincident.
[0050] Reflected light Lr is irradiated onto the inner circumferential surface and bottom surface (end surface) of the hole 131a1. Here, the body 131a is made of a metallic material that has high absorption of the wavelength of reflected light. Highly absorbent metallic materials include, for example, iron, nickel, copper, and other pure metals or alloys. Therefore, the reflected light Lr introduced into the hole 131a1 is absorbed by the body 131a, in other words, converted into thermal energy. The body 131a is provided with a heat sink 131b having fins that release the heat generated by the absorption of reflected light Lr to the outside. This promotes heat dissipation from the body 131a and suppresses the temperature of the body 131a from becoming excessively high. The heat sink 131b is an example of a cooling mechanism and can also be called a heat dissipation mechanism. In this embodiment, the heat dissipation mechanism is a so-called air-cooled heat dissipation mechanism that exchanges heat with the surrounding air, etc., but it is not limited to this, and may be a heat dissipation mechanism that exchanges heat with a medium such as water or a liquid.
[0051] Furthermore, to improve heat dissipation, the body 131a and heat sink 131b may be made of a metal material with higher thermal conductivity, at least partially. Examples of metal materials with higher thermal conductivity include copper, aluminum, nickel, and other pure metals or alloys. In addition, to improve both the absorption and heat dissipation of reflected light Lr, the body 131a may be made of pure nickel or an alloy.
[0052] Furthermore, the body 131a, acting as the absorption section, does not need to convert all of the energy of the reflected light Lr into thermal energy. It may be configured to convert only a portion of the energy of the reflected light Lr into thermal energy, thereby reducing the power of the reflected light Lr. In this case, the hole 131a1 may be a through hole rather than a bottomed hole as in this embodiment, and the open end opposite to the open end to which the connector 132 is attached may be open.
[0053] Furthermore, the shorter the wavelength of the laser light, the more easily the reflected light Lr leaks out of the optical fiber 12. Therefore, the configuration of this embodiment is particularly effective when the multiple light-emitting devices 111 include a light-emitting device 111 whose output laser light wavelength is 400 [nm] or more and 550 [nm] or more.
[0054] [Second Embodiment] Figure 3 is a side view (partial cross-sectional view) of the backlight detection mechanism 130B(130) of the second embodiment. The backlight detection mechanism 130B(130) includes a power reduction unit 131B(131), a connector 132, a heat sink 131b, and a sensor 142. The backlight detection mechanism 130B of this embodiment can be installed in place of the backlight detection mechanism 130A of the laser processing apparatus 100 of the first embodiment.
[0055] The power reduction unit 131B has the same configuration as the power reduction unit 131A of the first embodiment. However, in this embodiment, the hole 131a1 provided in the body 131a is a through hole. The optical fiber 12 that transmits the return light Lr includes two optical fibers 14 and 15 that are spaced apart from each other. Connectors 132 provided on optical fiber 14 and connectors 132 provided on optical fiber 15 are attached to the open ends of the hole 131a1, respectively. In other words, the body 131a supports the optical fiber 14 via the connectors 132 and also supports the optical fiber 15 via the connectors 132. Furthermore, the body 131a supports the optical fibers 14 and 15 in a state where they are spaced apart from each other in the direction of the optical axis.
[0056] In this configuration, the reflected light Lr from the optical fiber 14 is introduced into the hole 131a1 via a connector 132 that is optically connected to the optical fiber 14. A portion of the reflected light Lr introduced into the hole 131a1 is absorbed within the hole 131a1, and the remaining portion of the reflected light Lr that is not absorbed is coupled to the optical fiber 15 via a connector 132 that is optically connected to the optical fiber 15. On the side of the body 131a opposite to the optical fiber 15, a sensor 142 is provided to detect the intensity of the reflected light Lr transmitted through the optical fiber 15.
[0057] Sensor 142 is located on the opposite side of the optical head 120 (see Figure 1) from the optical fibers 14 and 15(12), and detects the intensity of the reflected light Lr output from the optical fiber 15(12).
[0058] In this configuration, the sensor 142 can detect the intensity of the reflected light Lr, which has been reduced in the power reduction unit 131B (131) to a value lower than the intensity limit of the sensor 142. Therefore, according to this embodiment, damage to the sensor 142 due to reflected light Lr can be suppressed. Optical fiber 14 is an example of a fourth optical fiber, optical fiber 15 is an example of a fifth optical fiber, and sensor 142 is an example of a second sensor.
[0059] Here, the detection intensity of the reflected light Lr in sensor 142, in other words, the power of the reflected light Lr reduced by the power reduction unit 131B (131), can be adjusted according to the specifications of body 131a. For example, the longer the distance between the two connectors 132, i.e., the longer the distance between optical fibers 14 and 15, the lower the detection intensity of the reflected light Lr in sensor 142 can be. Conversely, the shorter the distance, the higher the detection intensity of the reflected light Lr in sensor 142. Therefore, the detection intensity of the reflected light Lr in sensor 142 can be adjusted by adjusting this distance.
[0060] The controller 200 (see Figure 1) controls the operation of the light-emitting device 111 based on the detection signal from the sensor 142. For example, the controller 200 may stop the output of the light-emitting device 111 if the intensity of the detection signal is above a predetermined threshold. Alternatively, the controller 200 may control the operation of the light-emitting device 111 such that the output of the laser light from the light-emitting device 111 decreases as the intensity of the detection signal increases.
[0061] The same effects as those of the first embodiment can be obtained with this embodiment as well.
[0062] [Third Embodiment] Figure 4 is a side view (partial cross-sectional view) of the return light detection mechanism 130C(130) of the third embodiment. The return light detection mechanism 130C(130) includes a power reduction unit 131B(131), a connector 132, a heat sink 131b, and sensors 141 and 142. The return light detection mechanism 130C of this embodiment can be installed in place of the return light detection mechanism 130A of the laser processing apparatus 100 of the first embodiment.
[0063] As can be seen by comparing Figure 4 with Figure 3, the reflected light detection mechanism 130C of this embodiment has a configuration in which the sensor 141 of the first embodiment is added to the configuration of the second embodiment. In this case, the intensity of the reflected light Lr can be detected by both the sensor 141 and the sensor 142. The controller 200 (see Figure 1) controls the operation of the light-emitting device 111 based on the detection signals from the sensors 141 and 142. For example, the controller 200 may stop the output of the light-emitting device 111 if the intensity of the detection signal is above a predetermined threshold. Alternatively, the controller 200 may control the operation of the light-emitting device 111 such that the output of the laser light from the light-emitting device 111 decreases as the intensity of the detection signal increases.
[0064] The same effects as those of the first and second embodiments described above can be obtained with this embodiment as well. Furthermore, in this embodiment, since a dual system for detecting the intensity of the reflected light Lr can be constructed using sensors 141 and 142, the reliability of the reflected light detection mechanism 130 can be further enhanced, which is another advantage.
[0065] Furthermore, the sensor 142 may detect the intensity distribution in a cross-section perpendicular to the optical axis of the reflected light Lr. In this case, the controller 200 (see Figure 1) can determine whether or not the reflected light Lr was transmitted in a mode prone to failure.
[0066] [Fourth Embodiment] Figure 5 is a schematic diagram (partial cross-sectional view) of the power reduction unit 131D (131) of the fourth embodiment. The power reduction unit 131D of this embodiment can be installed in place of the power reduction unit 131 of the first to third embodiments described above.
[0067] In this embodiment, the diameter D2 of the hole 131a1 provided in the body 131a is smaller than the diameter D1 of the mounting portion of the connector 132 (see Figures 2-4) which is optically connected to the optical fiber 14. According to this embodiment, the absorption of reflected light Lr by the inner circumferential surface of the hole 131a1 can be promoted, and the power of the reflected light Lr transmitted on the opposite side from the optical head 120 can be reduced. Furthermore, when applied to the second and third embodiments, the detection intensity of the reflected light Lr in the sensor 142 can be further reduced. In that case, the detection intensity of the reflected light Lr in the sensor 142 can be adjusted by adjusting the diameter D2.
[0068] [Fifth Embodiment] Figure 6 is a schematic diagram (partial cross-sectional view) of the power reduction unit 131E (131) of the fifth embodiment. The power reduction unit 131E of this embodiment can be installed in place of the power reduction unit 131 of the first to third embodiments described above.
[0069] In this embodiment, a constricted portion 133 is provided in the middle of a hole 131a1 in the body 131a, in which the diameter of the hole 131a1 is partially narrowed. According to this embodiment, the reflected light Lr is partially blocked by the constricted portion 133, and the power of the reflected light Lr transmitted to the opposite side of the optical head 120 can be reduced by the absorption of the reflected light Lr by the constricted portion 133. Furthermore, when applied to the second and third embodiments, the detection intensity of the reflected light Lr in the sensor 142 can be further reduced. In that case, the detection intensity of the reflected light Lr in the sensor 142 can be adjusted by adjusting the specifications of the constricted portion 133, such as the aperture diameter. The constricted portion 133 is an example of a light-shielding portion. Note that the light-shielding portion only needs to have a shape that can partially block the reflected light Lr, and the shape of the light-shielding portion is not limited to the shape in Figure 6.
[0070] [Sixth Embodiment] Figure 7 is a schematic diagram (partial cross-sectional view) of the power reduction unit 131F (131) of the sixth embodiment. The power reduction unit 131F of this embodiment can be installed in place of the power reduction unit 131 of the first to third embodiments described above.
[0071] In this embodiment, a filter 134 that attenuates the reflected light Lr is provided in the middle of a hole 131a1 in the body 131a. According to this embodiment, the effect is obtained that the power of the reflected light Lr transmitted to the opposite side of the optical head 120 can be reduced by the amount that the reflected light Lr is attenuated by the filter 134. Furthermore, when applied to the second and third embodiments, the detection intensity of the reflected light Lr in the sensor 142 can be further reduced. In that case, the detection intensity of the reflected light Lr in the sensor 142 can be adjusted by adjusting the specifications of the filter 134, such as its transmittance.
[0072] [Seventh Embodiment] Figure 8 is a schematic diagram (partial cross-sectional view) of the power reduction unit 131G (131) of the seventh embodiment. The power reduction unit 131G of this embodiment can be installed in place of the power reduction unit 131 of the first to third embodiments described above.
[0073] In this embodiment, an expander 135 is provided in the middle of a hole 131a1 in the body 131a to expand the beam width (beam diameter) of the reflected light Lr. According to this embodiment, by expanding the beam width of the reflected light Lr with the expander 135, the power density of the reflected light Lr can be reduced. Furthermore, when applied to the second and third embodiments, the detection intensity of the reflected light Lr in the sensor 142 can be further reduced. In that case, the detection intensity of the reflected light Lr in the sensor 142 can be adjusted by adjusting the specifications of the expander 135, such as the refractive index and thickness.
[0074] [Eighth Embodiment] Figure 9 is a schematic diagram (partial cross-sectional view) of the power reduction unit 131H (131) of the eighth embodiment. The power reduction unit 131H of this embodiment can be provided in place of the power reduction unit 131 of the first embodiment.
[0075] In this embodiment, a recessed structure 136 is provided on the inner circumferential surface (side surface) and bottom surface (end surface) of the inner surface of the hole 131a1 provided in the body 131a. According to this embodiment, reflected light Lr is absorbed by the recessed structure 136 with a larger surface area, and any reflected light Lr that is not absorbed is reflected multiple times on the inner surface of the hole 131a1 and absorbed on that inner surface, thus achieving the effect of reducing the power of the reflected light Lr more efficiently. The depth of the recesses or the height of the protrusions of the recessed structure 136 is set to, for example, 1 / 3 or less of the inner diameter (diameter) of the hole 131a1.
[0076] In this embodiment, the hole 131a1 is a bottomed hole, but it may also be a through hole. If it is a through hole, the power reduction section 131H provided with the uneven structure 136 can be applied to the second and third embodiments. In this case, the uneven structure 136 can more efficiently reduce the detection intensity of the reflected light Lr in the sensor 142.
[0077] [Ninth Embodiment] Figure 10 is a schematic diagram (partial cross-sectional view) of the power reduction unit 131I (131) of the ninth embodiment. The power reduction unit 131I of this embodiment can be provided in place of the power reduction unit 131 of the first embodiment described above.
[0078] In this embodiment, the inner surface of the hole 131a1 provided in the body 131a has a tapered shape that narrows as it approaches the direction in which the reflected light Lr is incident on the hole 131a1 (to the left in Figure 10). According to this embodiment, the reflected light Lr is reflected multiple times on the inner surface and absorbed there, so the power of the reflected light Lr can be reduced more efficiently.
[0079] In this embodiment, the hole 131a1 is a bottomed hole, but it may also be a through hole. If it is a through hole, a power reduction section 131I provided with a tapered inner surface of the hole 131a1 can be applied to the second and third embodiments. In this case, the inner surface of the tapered hole 131a1 can more efficiently reduce the detection intensity of the reflected light Lr in the sensor 142.
[0080] [Tenth Embodiment] Figure 11 is a schematic diagram (partial cross-sectional view) of the power reduction unit 131J (131) of the tenth embodiment. The power reduction unit 131J of this embodiment can be provided in place of the power reduction unit 131 of the first embodiment described above.
[0081] In this embodiment, a metal layer 137 made of a material that more readily absorbs reflected light Lr is provided on the inner circumferential surface (side surface) and bottom surface (end surface) of the hole 131a1 provided in the body 131a. The metal layer 137 is, for example, a plating layer and is an example of an absorption layer. As the material of the metal layer 137, a material with a high absorption rate of light of the wavelength of the reflected light Lr, i.e., the wavelength of the laser light output by the light-emitting device 111, can be selected. Furthermore, it is preferable that the absorption rate of reflected light Lr of the metal layer 137 is greater than or equal to the absorption rate of reflected light Lr of the body 131a. The metal layer 137 is an example of an absorption layer.
[0082] According to this embodiment, a configuration capable of absorbing reflected light Lr can be realized relatively easily. Furthermore, by making the body 131a from a material with a higher thermal conductivity than the metal layer 137, the heat dissipation from the body 131a can be further improved.
[0083] [Embodiment No. 11] Figure 12 is a side view of the 11th embodiment of the return light detection mechanism 130K(130). The return light detection mechanism 130K(130) includes a leakage section 138K as a power reduction section 131 and a sensor 142. The return light detection mechanism 130K of this embodiment can be installed in place of the return light detection mechanism 130A of the first embodiment.
[0084] The leakage section 138K has a connector 132 optically connected to the optical fiber 14 and a connector 132 optically connected to the optical fiber 15. Each connector 132 is supported by a support member (not shown). A suitable gap G is provided between these two connectors 132. The return light Lr transmitted through the optical fiber 14 is output from the connector 132 optically connected to the optical fiber 14 to the gap G. A portion of the return light Lr output to the gap G is coupled to the optical fiber 15 via the connector 132 optically connected to the optical fiber 15 and is received by the sensor 142. The other portion of the return light Lr output to the gap G leaks out. The leakage section 138K is an example of a first leakage section.
[0085] According to this embodiment, the amount of reflected light Lr that leaks from the gap G in the leakage section 138K can be reduced, thereby lowering the detection intensity of the reflected light Lr in the sensor 142. In addition, the optical axis C1 of the optical fiber 14 and connector 132 and the optical axis C2 of the optical fiber 15 and connector 132 may be misaligned with each other. In this case, the greater the misalignment between optical axis C1 and optical axis C2, the easier it is for light to leak from the leakage section 138K. Therefore, by adjusting the amount of axial misalignment between optical axis C1 and optical axis C2, the amount of reflected light Lr leakage can be adjusted, and consequently, the detection intensity of the reflected light Lr in the sensor 142 can be adjusted.
[0086] [Twelfth Embodiment] Figure 13 is a side view of the 12th embodiment of the return light detection mechanism 130L(130). The return light detection mechanism 130L(130) includes a leakage section 138L as a power reduction section 131 and a sensor 142. The return light detection mechanism 130L of this embodiment can be installed in place of the return light detection mechanism 130A of the first embodiment.
[0087] The leakage section 138L includes a connector 132 optically connected to the optical fiber 14 and an end cap 132L optically connected to the optical fiber 15. The connector 132 and the end cap 132L are each supported by a support member (not shown). A suitable gap G is provided between the connector 132 and the end cap 132L. The return light Lr transmitted through the optical fiber 14 is output from the connector 132 optically connected to the optical fiber 14 to the gap G. A portion of the return light Lr output to the gap G is coupled to the optical fiber 15 via the end cap 132L optically connected to the optical fiber 15 and is received by the sensor 142. The remaining portion of the return light Lr output to the gap G leaks out. The leakage section 138L is an example of a first leakage section. The end cap 132L is an example of an optical component that transmits the return light Lr and may also be called an end member.
[0088] According to this embodiment, the amount of reflected light Lr that leaks out through the gap G of the leakage portion 138L can reduce the detection intensity of the reflected light Lr in the sensor 142. Furthermore, in this embodiment, the amount of reflected light Lr leakage can be adjusted by adjusting the size of the end cap 132L, the area of the end face (the surface facing the gap G), the transmission loss, the transmittance, and other specifications, and consequently the detection intensity of the reflected light Lr in the sensor 142 can be adjusted.
[0089] [13th Embodiment] Figure 14 is a side view of the 13th embodiment of the backlight detection mechanism 130M(130). The backlight detection mechanism 130K(130) includes a leakage section 138K as a power reduction section 131 and a sensor 142. The backlight detection mechanism 130K of this embodiment can be provided in place of the backlight detection mechanism 130A of the first embodiment.
[0090] The leak section 138M has the same configuration as the leak section 138K of the 11th embodiment (see Figure 12). Therefore, the same effects as the 11th embodiment can be obtained with this embodiment as well. The leak section 138M is an example of a first leak section.
[0091] Furthermore, in this embodiment, a curved portion 15a is provided in the optical fiber 15. Reflected light Lr leaks from the curved portion 15a. In other words, the curved portion 15a is a leakage portion 139 from which reflected light Lr leaks. Therefore, according to this embodiment, the detection intensity of reflected light Lr in the sensor 142 can be reduced by the amount of reflected light Lr leaking from the curved portion 15a. In addition, in this embodiment, the amount of reflected light Lr leakage can be adjusted by adjusting the curvature, bending shape, radius, length and number of bending sections of the curved portion 15a, and consequently, the detection intensity of reflected light Lr in the sensor 142 can be adjusted. The leakage portion 139 is an example of a second leakage portion, and the optical fiber 15 is an example of a sixth optical fiber. Note that the curved portion 15a may also be provided in the optical fiber 14.
[0092] [14th Embodiment] [Configuration of the laser processing machine] Figure 15 is a schematic diagram of the 14th embodiment of the laser processing apparatus 100N(100). The laser processing apparatus 100N has an additional light-emitting device 112 compared to the laser processing apparatus 100A of the first embodiment. Accordingly, the laser light output from the light-emitting device 112 is introduced into the optical head 120N(120) via the optical fiber 11, and the optical head 120N is configured to combine the laser light output from the light-emitting device 111 and the laser light output from the light-emitting device 112.
[0093] The light-emitting device 112 is a laser device that outputs laser light. The light-emitting device 112 outputs laser light with a longer wavelength than the laser light output by the light-emitting device 111, for example, laser light with a wavelength of 800 nm or more and 1200 nm or less. The light-emitting device 112 includes, for example, a fiber laser as a light source.
[0094] The optical fiber 11, which is optically connected to the light-emitting device 112, transmits the laser light output from the light-emitting device 112. The optical fiber 11 is, for example, a single-mode optical fiber.
[0095] The laser light output from the light-emitting device 112 is input to the optical head 120 via the optical fiber 11. This laser light is then input to the focusing lens 122 via the collimating lens 121-1 (121), mirror 123, and filter 124.
[0096] On the other hand, the laser light output from the multiple light-emitting devices 111 is input to the optical head 120 via the optical fiber 11, coupler 10, and optical fiber 13, similar to the first embodiment. The laser light is then input to the focusing lens 122 via the collimating lens 121-2 (121) and filter 124.
[0097] The filter 124 transmits the laser light from the mirror 123 and reflects the laser light from the collimating lens 121-2, directing it towards the focusing lens 122. The filter 124 is, for example, a dichroic mirror that transmits or reflects laser light depending on the wavelength.
[0098] From the focusing lens 122, that is, from the optical head 120N, a laser beam L is emitted, which includes the laser beam output by the light-emitting device 111 and the laser beam output by the light-emitting device 112, and is irradiated onto the surface Wa of the workpiece W.
[0099] In this case, the reflected light detection mechanism 130 can incorporate the reflected light detection mechanism 130 of the above embodiment. In this embodiment, it is preferable to incorporate the reflected light detection mechanism 130C of the third embodiment (see Figure 4) as the reflected light detection mechanism 130. In this case, for example, a sensor 141 that detects the leakage of reflected light Lr from the outer circumference of the optical fiber 14 (12) may be used to detect the intensity of the reflected light Lr for shorter wavelength laser light output from the light-emitting device 111, and a sensor 142 that detects the reflected light Lr whose power has been reduced by the power reduction unit 131 may be used to detect the intensity of the reflected light Lr for longer wavelength laser light output from the light-emitting device 112. The shorter the wavelength, the more easily it scatters and the more easily it leaks from the outer circumference of the optical fiber 14 (12). Therefore, it is easy to set up the use of sensors 141 and 142 according to wavelength as described above. In this case, in order to more reliably separate the detection wavelength, a filter that filters the input reflected light Lr may be provided for at least one of the sensors 141 and 142.
[0100] Although embodiments of the present invention have been illustrated above, these embodiments are merely examples and are not intended to limit the scope of the invention. The above embodiments can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention. Furthermore, each configuration, shape, and other specifications (structure, type, orientation, model, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be modified as appropriate. [Explanation of symbols]
[0101] 100, 100A, 100N… Laser processing equipment 10...Coupler (wave coupling section) 11… Optical fiber (First Optical Fiber) 12… Optical fiber (second optical fiber) 13… Optical fiber (third optical fiber) 14… Optical fiber (fourth optical fiber) 15… Optical fiber (Fifth optical fiber, Sixth optical fiber) 15a...Curved section 111... Light-emitting device 112... Light-emitting device 120, 120A, 120N… Optical heads 121, 121-1, 121-2… Collimating lenses 122... Focusing lens 123...Mirror 124... Filter 130, 130A~130C, 130K~130M... Reflection light detection mechanism 131, 131A, 131B, 131D~131J... Power reduction section 131a...Body (absorbent part) 131a1…hole 131b... Heatsink (cooling mechanism) 132… Connector 132L… End cap 133...Stricture area (light shielding area) 134...Filter (attenuation section) 135... Expander 136…Uneven structure 137…Metal layer (absorption layer, absorption part) 138K~138M... Leakage section (First leakage section) 139... Leakage area (Second leakage area) 141...Sensor (First Sensor) 142...Sensor (Second Sensor) 200... Controller C1,C2…optical axis D1,D2…Diameter G... Gap L... Laser light Lr... Reflected light W...Object Wa... Surface
Claims
1. A light-emitting device that emits laser light, A first optical fiber that transmits laser light output from the aforementioned light-emitting device, An optical head that emits laser light transmitted through the first optical fiber toward the workpiece, A second optical fiber that transmits the return light from the optical head, A first sensor that detects shorter wavelength light from the leaked light of the return light that leaks from the outer circumference of the second optical fiber, A second sensor is provided on the side of the second optical fiber opposite to the optical head and detects the longer wavelength light among the reflected light output from the second optical fiber. A power reduction unit that reduces the power of the reflected light input to the second sensor, A laser processing device equipped with [specific features / equipment].
2. The laser processing apparatus according to claim 1, further comprising a controller that controls the operation of the light-emitting device based on at least one of the detection signal from the first sensor and the detection signal from the second sensor.
3. The laser processing apparatus according to claim 1 or 2, wherein the second sensor detects the intensity distribution of the reflected light.
4. The laser processing apparatus according to any one of claims 1 to 3, wherein the power reduction unit has an absorption unit that absorbs the reflected light.
5. The laser processing apparatus according to claim 4, wherein the absorbing part has a body provided with a hole into which the reflected light is introduced.
6. The laser processing apparatus according to claim 5, wherein the inner circumferential surface of the hole is provided with an uneven structure.
7. The laser processing apparatus according to claim 5 or 6, wherein the inner circumferential surface of the hole has a tapered shape in which the inner diameter narrows as it approaches the direction in which the reflected light is incident on the hole.
8. The laser processing apparatus according to any one of claims 5 to 7, wherein the absorbing portion has an absorbing layer provided on the inner circumferential surface of the hole that absorbs the reflected light.
9. The second optical fiber comprises a fourth optical fiber and a fifth optical fiber provided with a gap between it and the fourth optical fiber, to which the reflected light output from the fourth optical fiber is coupled. The laser processing apparatus according to any one of claims 5 to 8, wherein the body supports the fourth optical fiber and the fifth optical fiber spaced apart in the direction of the optical axis of the reflected light in the hole.
10. A laser processing apparatus according to any one of claims 5 to 9, comprising a cooling mechanism that is thermally connected to the body and cools the body.
11. The laser processing apparatus according to any one of claims 1 to 10, wherein the power reduction unit is equipped with a light-shielding unit that partially blocks the reflected light.
12. The laser processing apparatus according to any one of claims 1 to 11, wherein the power reduction unit is equipped with a filter that attenuates the reflected light.
13. The laser processing apparatus according to any one of claims 1 to 12, further comprising an expander for widening the width of the reflected light beam as the power reduction unit.
14. The laser processing apparatus according to any one of claims 1 to 13, wherein the power reduction unit has a leakage unit for leaking the reflected light.
15. The second optical fiber comprises a fourth optical fiber and a fifth optical fiber provided with a gap between it and the fourth optical fiber, to which the reflected light output from the fourth optical fiber is coupled. The laser processing apparatus according to claim 14, wherein the power reduction unit has a first leakage unit through which the reflected light leaks, as the leakage unit.
16. The laser processing apparatus according to claim 15, wherein the optical axis of the fourth optical fiber and the optical axis of the fifth optical fiber are offset from each other.
17. The second optical fiber has a sixth optical fiber having a curved portion, The laser processing apparatus according to any one of claims 14 to 16, wherein the power reduction section has a second leakage section from which the reflected light leaks out of the curved section.
18. Multiple light-emitting devices as the aforementioned light-emitting devices, The plurality of first optical fibers, each of which transmits the laser light from the light-emitting device, A wave combining unit that combines the laser light from the plurality of light-emitting devices transmitted through the plurality of first optical fibers, A third optical fiber transmits the laser light combined in the multiplexing section to the optical head. Equipped with, The laser processing apparatus according to any one of claims 1 to 17, wherein the second optical fiber is optically connected to the multiplexing section on the side opposite to the third optical fiber with respect to the multiplexing section.