Laser beam irradiation device and laser processing device

Abstract

A laser light irradiation device (1) comprises a plurality of laser light sources (10), an optical fiber (30), and a coupling optical system (20). The coupling optical system (20) includes a reducing optical system (22). The reducing optical system (22) includes a lens (23a) and a lens (24a). The lens (23a) is formed from a first glass material. The lens (24a) is formed from a second glass material. A second energy gap of the second glass material is greater than a first energy gap of the first glass material.

Description

[Technical Field]

[0001] This disclosure relates to a laser light irradiation device and a laser processing device. [Background technology]

[0002] Japanese Patent Publication No. 2007-163947 (Patent Document 1) discloses a multiplexing optical system that couples multiple laser beams emitted from multiple semiconductor lasers into an optical fiber. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-163947 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The first object of this disclosure is to provide a laser irradiation apparatus capable of stably coupling laser beams emitted from each of a plurality of laser light sources over a long period of time using optical fibers. The second object of this disclosure is to provide a laser processing apparatus capable of stably processing a workpiece over an even longer period of time. [Means for solving the problem]

[0005] The laser light irradiation apparatus of this disclosure comprises a plurality of laser light sources, an optical fiber, and a coupling optical system. Each of the plurality of laser light sources emits a laser beam. The coupling optical system is positioned between the plurality of laser light sources and the optical fiber and couples the laser beams into the optical fiber. The coupling optical system includes a reduction optical system. The reduction optical system includes a first lens and a second lens. In the optical path of the laser beam, the first lens is positioned closer to the plurality of laser light sources than the second lens. The second beam cross-sectional area of ​​the laser beam at the exit surface of the second lens is smaller than the first beam cross-sectional area of ​​the laser beam at the incident surface of the first lens. The first lens is formed of a first glass material. The second lens is formed of a second glass material. The second energy gap of the second glass material is larger than the first energy gap of the first glass material.

[0006] The laser processing apparatus of this disclosure includes a laser light irradiation device of this disclosure. [Effects of the Invention]

[0007] The laser irradiation apparatus of this disclosure allows for the stable coupling of laser beams emitted from each of multiple laser light sources over a long period of time using optical fibers. The laser processing apparatus of this disclosure allows for the stable processing of workpieces over an even longer period of time. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the laser light irradiation device according to the embodiment. [Figure 2] This is a schematic perspective view showing an example of a laser light source included in the laser light irradiation device of the embodiment. [Figure 3] This figure shows a graph of the light intensity distribution in the fast axis direction of the laser beam emitted from the laser light source included in the laser light irradiation device of the embodiment. [Figure 4] This figure shows a graph of the light intensity distribution in the slow axis direction of the laser beam emitted from the laser light source included in the laser light irradiation device of the embodiment. [Figure 5]This is a schematic diagram of a modified example of a laser light irradiation device. [Figure 6] This is a schematic diagram of the laser light irradiation device according to the embodiment. [Figure 7] This figure shows graphs illustrating the change in optical output over time of the laser light irradiation devices in the examples and comparative examples. [Modes for carrying out the invention]

[0009] Embodiments of the present disclosure will be described below. The same components will be given the same reference numerals, and their descriptions will not be repeated.

[0010] An embodiment of the laser light irradiation device 1 will be described with reference to Figures 1 to 4. The laser light irradiation device 1 comprises a plurality of laser light sources 10, a coupling optical system 20, and an optical fiber 30. The laser light irradiation device 1 may further comprise a plurality of packages 9.

[0011] Each of the multiple packages 9 houses a corresponding laser light source 10 from among the multiple laser light sources 10. Each of the multiple packages 9 is, for example, a TO-CAN package.

[0012] Each of the multiple laser light sources 10 emits a corresponding laser beam 19. The multiple laser beams 19 have, for example, the same wavelength. Each of the multiple laser beams 19 has, for example, a wavelength between 380 nm and 550 nm. Each of the multiple laser light sources 10 is, for example, a continuous wave (CW) laser light source. Each of the multiple laser light sources 10 is, for example, a high-power laser light source having an optical output of 5 W or more. The multiple laser light sources 10 collectively have an optical output of, for example, 1 kW or more.

[0013] As shown in FIG. 2, each of the plurality of laser light sources 10 is, for example, a laser diode. The laser diode includes a substrate 11, a lower cladding layer 12, an active layer 13, an upper cladding layer 14, electrodes 15 and 16, and an insulating layer 17. The lower cladding layer 12 is formed on the substrate 11. The active layer 13 is formed on the lower cladding layer 12. The upper cladding layer 14 is formed on the active layer 13. The active layer 13 is sandwiched between the lower cladding layer 12 and the upper cladding layer 14. The electrode 15 is formed on the substrate 11. The electrode 15 may be formed on the lower cladding layer 12 instead of on the substrate 11. The electrode 16 is formed on the upper cladding layer 14.

[0014] When current is injected into the active layer 13 through the electrodes 15 and 16, a laser beam 19 is emitted from the end face of the active layer 13. In a cross section perpendicular to the optical axis O of the laser beam 19, the laser beam 19 has an elliptical shape. In a cross section perpendicular to the optical axis O of the laser beam 19, the fast axis direction of the laser beam 19 is the thickness direction of the active layer 13, and the slow axis direction of the laser beam 19 is the width direction of the active layer 13. The x-axis direction shown in FIG. 1 is the fast axis direction of the laser beam 19. The y-axis direction shown in FIG. 1 is the slow axis direction of the laser beam 19. The z-axis direction shown in FIG. 1 is the optical axis direction of the laser beam 19.

[0015] The plurality of laser light sources 10 may be solid-state lasers or fiber lasers. The cross-sectional shape of the laser beam 19 in a cross section perpendicular to the optical axis O of the laser beam 19 is not limited to an ellipse and may be circular or the like.

[0016] As shown in FIG. 1, the coupling optical system 20 is disposed between the plurality of laser light sources 10 and the optical fiber 30. The coupling optical system 20 couples the laser beams 19 emitted from each of the plurality of laser light sources 10 to the optical fiber 30. The coupling optical system 20 includes a plurality of collimating lenses 21, a reducing optical system 22, and a condenser lens 26.

[0017] Multiple collimating lenses 21 are arranged between multiple laser light sources 10 and the reduction optical system 22. Each of the multiple collimating lenses 21 is provided for a corresponding laser light source 10. Each of the multiple collimating lenses 21 collimates a corresponding laser beam 19. The multiple collimating lenses 21 are formed of the same glass material as, for example, lens 23a, which will be described later. That is, the multiple collimating lenses 21 are formed of, for example, the first glass material, which will be described later.

[0018] The reduction optical system 22 reduces the spacing between the multiple laser beams 19. Therefore, the reduction optical system 22 can cause the multiple laser beams 19 to be incident within the range of the numerical aperture NA of the optical fiber 30. The reduction optical system 22 includes lens 23a and lens 24a. In the optical path of the laser beams 19, lens 23a is positioned closer to the multiple laser light sources 10 than lens 24a. In the optical path of the laser beams 19, lens 23a is positioned between the multiple laser light sources 10 and lens 24a.

[0019] The lens 23a has an incident surface 23i and an exit surface 23j. The lens 23a has positive power. The lens 23a is, for example, a plano-convex lens with its convex surface facing the multiple laser light sources 10.

[0020] Lens 24a has an incident surface 24i and an exit surface 24j. Lens 24a has negative power. Lens 24a is, for example, a plano-concave lens with its concave surface facing the optical fiber 30.

[0021] In this embodiment, the reduction optical system 22 reduces the spacing between the multiple laser beams 19 in the fast axis direction (x direction) and also reduces the beam size (e.g., beam diameter) of each of the multiple laser beams 19 in the fast axis direction. Therefore, the second beam cross-sectional area of ​​each of the multiple laser beams 19 at the exit surface 24j of lens 24a is smaller than the first beam cross-sectional area of ​​each of the multiple laser beams 19 at the incident surface 23i of lens 23a. In this specification, the cross-sectional area of ​​the laser beam 19 is defined as the light intensity of the laser beam 19 in a cross-section perpendicular to the optical axis of the laser beam 19 being 1 / e of the peak light intensity of the laser beam 19. 2 This is the area of ​​the region of the laser beam 19. For example, if the laser beam 19 has an elliptical shape, it is 1 / e of the peak light intensity of the laser beam 19. 2 The region of the laser beam 19 is such that the major axis W is in the fast axis direction. x (See Figure 3) It has a minor axis W in the throw axis direction, and y It has an elliptical shape (see Figure 4). Therefore, the cross-sectional area of ​​the laser beam 19 is the major axis W. x and minor axis W y It is given by the area of ​​an ellipse having [a certain property].

[0022] The second power density of the laser beam 19 at the exit surface 24j of lens 24a is greater than the first power density of the laser beam 19 at the incident surface 23i of lens 23a. The first power density of the laser beam 19 at the incident surface 23i of lens 23a is, for example, 300 W / cm². 2 It is less than . The second power density of the laser beam 19 at the exit surface 24j of lens 24a is, for example, 300 W / cm². 2 That concludes the explanation. The second power density of the laser beam 19 at the exit surface 24j of lens 24a is, for example, more than twice the first power density of the laser beam 19 at the incident surface 23i of lens 23a. In this specification, the power density of the laser beam 19 is given by dividing the power of the laser beam 19 by the cross-sectional area of ​​the laser beam 19.

[0023] Lens 23a is formed of a first glass material. Lens 24a is formed of a second glass material. The second energy gap of the second glass material is greater than the first energy gap of the first glass material. For example, the first energy gap is 6.6 eV or less, and the second energy gap is greater than 6.6 eV. The second energy gap is, for example, 1.4 times or more the first energy gap. The second energy gap is, for example, greater than twice the photon energy of the laser beam 19. The photon energy E (eV) of the laser beam 19 is given by equation (1), where h is Planck's constant, c is the speed of light in a vacuum, e is the elementary charge, and λ is the wavelength of the laser beam 19.

[0024]

number

[0025] The first glass material is, for example, BK7. BK7 has an energy gap in the range of 4.5 eV to 5.7 eV. The second glass material is, for example, synthetic quartz. Synthetic quartz has an energy gap in the range of 8 eV to 9 eV.

[0026] BK7 and synthetic quartz have high transmittance to light with wavelengths in the visible range (e.g., wavelengths in the range of 380 nm to 750 nm). BK7 is cheaper to manufacture and easier to process than synthetic quartz. Therefore, BK7 makes it possible to manufacture lenses at a lower cost than synthetic quartz. The refractive index of BK7 is greater than that of synthetic quartz. Therefore, BK7 can reduce the size of the lens itself and the size of the optical system including the lens compared to synthetic quartz. The temperature coefficient of the refractive index of BK7 is 2.6 ppm / °C, while the temperature coefficient of the refractive index of synthetic quartz is 10.6 ppm / °C. The temperature dependence of the refractive index of BK7 is smaller than that of synthetic quartz. By using BK7 as the glass material for lenses, it is possible to reduce fluctuations in the output of the laser beam from the laser irradiation device in response to temperature changes in the laser irradiation device.

[0027] The reduction optical system 22 reduces the interval between the plurality of laser beams 19 in both the fast axis direction (x direction) and the slow axis direction (y direction), and may also reduce the beam size (e.g., beam diameter) of each of the plurality of laser beams 19 in both the fast axis direction (x direction) and the slow axis direction. Such a reduction optical system 22 is suitable, for example, when each of the plurality of laser beams 19 has a circular cross-sectional shape.

[0028] The condenser lens 26 is disposed between the reduction optical system 22 and the optical fiber 30. The condenser lens 26 condenses the laser beam 19 emitted from the reduction optical system 22 onto the core 31 of the optical fiber 30. The condenser lens 26 is, for example, a biconvex positive lens. The condenser lens 26 is formed of, for example, the same optical material as the lens 24a. That is, the condenser lens 26 is formed of, for example, the second optical material.

[0029] The optical fiber 30 includes a core 31 and a cladding 32. The core 31 is surrounded by the cladding 32. The core 31 has a refractive index greater than that of the cladding 32. The plurality of laser beams 19 emitted from the plurality of laser light sources 10 propagate through the core 31. The plurality of laser beams 19 are multiplexed in the core 31 and emitted from the core 31 as a laser beam 35. The optical fiber 30 is, for example, a silica optical fiber. When the optical fiber 30 is disposed in air, the numerical aperture NA of the optical fiber 30 and the maximum incident angle θ of light that can be coupled to the optical fiber 30 max are given by Equation (2). n core represents the refractive index of the core 31, and n clad represents the refractive index of the cladding 32.

[0030]

Equation

[0031] [Modified Example] Referring to Figure 5, a modified example of this embodiment, the laser light irradiation device 1b, will be described. The laser light irradiation device 1b has the same configuration as the laser light irradiation device 1, but differs from the laser light irradiation device 1 in that the reduction optical system 22 includes multiple lenses 23a, 23b and multiple lenses 24a, 24b. In the laser light irradiation device 1b, the multiple lenses 23a, 23b constitute the first reduction optical system, and the multiple lenses 24a, 24b constitute the second reduction optical system. The reduction optical system 22 includes the first reduction optical system and the second reduction optical system. The first reduction optical system and the second reduction optical system are arranged in series along the respective optical axes of the multiple laser beams 19. Therefore, even if the number of multiple laser light sources 10 increases, the reduction optical system 22 can cause the multiple laser beams 19 to be incident within the range of the numerical aperture NA of the optical fiber 30.

[0032] The incident surface 23i of the multiple lenses 23a and 23b is the incident surface of lens 23a. The exit surface 23j of the multiple lenses 23a and 23b is the exit surface of lens 23b. Lens 23a has positive power. Lens 23a is, for example, a plano-convex lens with its convex surface facing the multiple laser light sources 10. Lens 23b has negative power. Lens 23b is, for example, a plano-concave lens with its concave surface facing the optical fiber 30.

[0033] The incident surface 24i of the multiple lenses 24a and 24b is the incident surface of lens 24a. The exit surface 24j of the multiple lenses 24a and 24b is the exit surface of lens 24b. Lens 24a has positive power. Lens 24a is, for example, a plano-convex lens with its convex surface facing the multiple laser light sources 10. Lens 24b has negative power. Lens 24b is, for example, a plano-concave lens with its concave surface facing the optical fiber 30.

[0034] Multiple lenses 23a and 23b reduce the spacing between multiple laser beams 19 in the fast axis direction (x direction) and also reduce the beam size (e.g., beam diameter) of each of the multiple laser beams 19 in the fast axis direction. Multiple lenses 24a and 24b also reduce the spacing between multiple laser beams 19 in the fast axis direction (x direction) and also reduce the beam size (e.g., beam diameter) of each of the multiple laser beams 19 in the fast axis direction. Therefore, the second beam cross-sectional area of ​​each of the multiple laser beams 19 at the exit surface 24j of the multiple lenses 24a and 24b is smaller than the first beam cross-sectional area of ​​each of the multiple laser beams 19 at the incident surface 23i of the multiple lenses 23a and 23b.

[0035] The second power density of the laser beam 19 at the exit surface 24j of the multiple lenses 24a, 24b is greater than the first power density of the laser beam 19 at the incident surface 23i of the multiple lenses 23a, 23b. The first power density of the laser beam 19 at the incident surface 23i of the multiple lenses 23a, 23b is, for example, 300 W / cm². 2 It is less than . The second power density of the laser beam 19 at the emission surface 24j of the multiple lenses 24a, 24b is, for example, 300 W / cm². 2 That concludes the explanation. The second power density of the laser beam 19 at the exit surface 24j of the multiple lenses 24a, 24b is, for example, more than twice the first power density of the laser beam 19 at the incident surface 23i of the multiple lenses 23a, 23b.

[0036] Multiple lenses 23a, 23b are formed from a first glass material. The number of lenses formed from the first glass material is not limited to two, but may be three or more. Multiple lenses 24a, 24b are formed from a second glass material, not limited to two. The number of lenses formed from the second glass material may be three or more. The second energy gap of the second glass material is greater than the first energy gap of the first glass material. For example, the first energy gap is 6.6 eV or less, and the second energy gap is greater than 6.6 eV. The second energy gap is, for example, 1.4 times or more the first energy gap. The second energy gap is, for example, greater than twice the photon energy of the laser beam 19. The first glass material is, for example, BK7. The second glass material is, for example, synthetic quartz.

[0037] Multiple lenses 23a, 23b may reduce the spacing between multiple laser beams 19 in both the fast axis direction (x direction) and the slow axis direction (y direction), and may also reduce the beam size (e.g., beam diameter) of each of the multiple laser beams 19 in both the fast axis direction (x direction) and the slow axis direction (y direction). Multiple lenses 24a, 24b may reduce the spacing between multiple laser beams 19 in both the fast axis direction (x direction) and the slow axis direction (y direction), and may also reduce the beam size (e.g., beam diameter) of each of the multiple laser beams 19 in both the fast axis direction (x direction) and the slow axis direction (y direction). Such a reduction optical system 22 is suitable, for example, when each of the multiple laser beams 19 has a circular cross-sectional shape.

[0038] Referring to Figure 6, the laser processing apparatus 2 of this embodiment will be described. The laser processing apparatus 2 processes a workpiece 40 using a laser beam 35. Specifically, the workpiece 40 is heated by irradiating it with the laser beam 35. The material constituting the workpiece 40 melts or evaporates. In this way, the workpiece 40 is processed using the laser beam 35. In this specification, processing includes, for example, welding, cutting, and forming a recess in the workpiece 40. The laser processing apparatus 2 comprises a laser light irradiation device 41, an irradiation mechanism 42, a moving mechanism 43, a workpiece mounting table 44, and a controller 45.

[0039] The laser beam irradiation device 41 is either the laser beam irradiation device 1 (see Figure 1) or the laser beam irradiation device 1b (see Figure 5). The workpiece 40 is placed on the workpiece mounting table 44. The irradiation mechanism 42 includes a focusing lens (not shown). The irradiation mechanism 42 focuses the laser beam 35 emitted from the optical fiber 30 using the focusing lens and irradiates the workpiece 40. The moving mechanism 43 includes a motor (not shown). The moving mechanism 43 moves the irradiation mechanism 42 to move the irradiation area of ​​the laser beam 35 on the workpiece 40.

[0040] The controller 45 controls the laser beam irradiation device 41 and the moving mechanism 43. For example, the controller 45 controls the multiple laser light sources 10 included in the laser beam irradiation device 41. The controller 45 also controls the motors included in the moving mechanism 43.

[0041] The controller 45 is a microcomputer that includes, for example, a processor, RAM (Random Access Memory), and a memory device such as ROM (Read Only Memory). A CPU (Central Processing Unit) may be used as the processor. RAM functions as working memory for temporarily storing data processed by the processor. The memory device stores, for example, programs executed by the processor. By executing the programs stored in the memory device, the controller 45 controls the laser beam irradiation device 41 and the moving mechanism 43. The various processes in the controller 45 are not limited to being performed by software, but may also be performed by dedicated hardware (electronic circuits).

[0042] [Operation of this embodiment] Referring to Figure 7, the operation of the laser light irradiation apparatus 1 and 1b of this embodiment will be explained while comparing the laser light irradiation apparatus of the embodiment with the laser light irradiation apparatus of the comparative example. The laser light irradiation apparatus of the embodiment is configured similarly to the modified laser light irradiation apparatus 1b of this embodiment. In the laser light irradiation apparatus of the embodiment, the multiple laser light sources 10 are blue laser diodes that emit blue laser beams, the first glass material is made of BK7, the second glass material is made of synthetic quartz, and the first power density of the laser beam 19 at the incident surface 23i of the multiple lenses 23a and 23b is 231 W / cm². 2 Therefore, the second power density of the laser beam 19 at the emission surface 24j of the multiple lenses 24a, 24b is 486 W / cm². 2 The comparative example laser irradiation device is configured similarly to the example laser irradiation device, but in the comparative example laser irradiation device, the first glass material and the second glass material are made of BK7.

[0043] As shown in Figure 7, in the comparative example laser irradiation device, the intensity of the laser beam 35 output from the optical fiber 30 decreases significantly as the irradiation time of the laser beam 35 increases. The reason for this is thought to be as follows.

[0044] The bandcap energy of BK7 is greater than the photon energy of the laser beam 19. Therefore, BK7 is essentially transparent to the laser beam 19 and does not absorb it. However, the bandcap energy of BK7 is less than twice the photon energy of the laser beam 19. Therefore, as the optical output of each of the multiple laser light sources 10 increases and the power density of the laser beam 19 in the multiple lenses 24a and 24b increases, two-photon absorption occurs in the multiple lenses 24a and 24b. Due to the two-photon absorption, the chemical bonds of the glass forming the multiple lenses 24a and 24b are broken, and the density of the glass in the multiple lenses 24a and 24b increases. The refractive index of the multiple lenses 24a and 24b increases, and the coupling efficiency of the laser beam 19 from the coupling optical system 20 to the optical fiber 30 decreases. The laser beams 19 emitted from each of the multiple laser light sources 10 cannot be stably coupled by the optical fiber 30 for a long period of time. In this way, the intensity of the laser beam 35 output from the optical fiber 30 is greatly reduced.

[0045] In contrast, in the laser irradiation device of the embodiment, even when the irradiation time of the laser beam 35 is extended, the decrease in the intensity of the laser beam 35 output from the optical fiber 30 is suppressed. The reason for this is thought to be as follows.

[0046] The bandcap energy of synthetic quartz is greater than twice the photon energy of the laser beam 19. Therefore, even if the optical output of each of the multiple laser light sources 10 increases and the power density of the laser beam 19 in the multiple lenses 24a and 24b increases, two-photon absorption does not occur in the multiple lenses 24a and 24b. Even if the irradiation time of the laser beam 35 is extended, the refractive index of the multiple lenses 24a and 24b hardly changes, and the coupling efficiency of the laser beam 19 from the coupling optical system 20 to the optical fiber 30 also hardly changes. The laser beams 19 emitted from each of the multiple laser light sources 10 can be stably coupled by the optical fiber 30 over a long period of time. In this way, the decrease in the intensity of the laser beam 35 output from the optical fiber 30 is suppressed.

[0047] [Pattern] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0048] (Section 1) A laser light irradiation device according to one embodiment comprises a plurality of laser light sources, an optical fiber, and a coupling optical system. Each of the plurality of laser light sources emits a laser beam. The coupling optical system is arranged between the plurality of laser light sources and the optical fiber and couples the laser beams into the optical fiber. The coupling optical system includes a reduction optical system. The reduction optical system includes a first lens and a second lens. In the optical path of the laser beam, the first lens is positioned closer to the plurality of laser light sources than the second lens. The second beam cross-sectional area of ​​the laser beam at the exit surface of the second lens is smaller than the first beam cross-sectional area of ​​the laser beam at the incident surface of the first lens. The first lens is made of a first glass material. The second lens is made of a second glass material. The second energy gap of the second glass material is larger than the first energy gap of the first glass material.

[0049] Therefore, even if the laser beam irradiation time is extended, the refractive index of the second lens hardly changes, and the coupling efficiency of the laser beam from the coupling optical system to the optical fiber also hardly changes. Laser beams emitted from each of multiple laser light sources can be stably coupled over a long period of time using optical fibers.

[0050] (Article 2) In the laser light irradiation apparatus described in Article 1, the laser beam has a wavelength of 380 nm or more and 550 nm or less, the first energy gap is 6.6 eV or less, and the second energy gap is greater than 6.6 eV.

[0051] Therefore, even if the laser beam irradiation time is extended, the refractive index of the second lens hardly changes, and the coupling efficiency of the laser beam from the coupling optical system to the optical fiber also hardly changes. Laser beams emitted from each of multiple laser light sources can be stably coupled over a long period of time using optical fibers.

[0052] (Article 3) In the laser light irradiation apparatus described in Article 1 or Article 2, the second glass material is synthetic quartz.

[0053] Therefore, even if the laser beam irradiation time is extended, the refractive index of the second lens hardly changes, and the coupling efficiency of the laser beam from the coupling optical system to the optical fiber also hardly changes. Laser beams emitted from each of multiple laser light sources can be stably coupled over a long period of time using optical fibers.

[0054] (Article 4) In the laser light irradiation apparatus described in any one of paragraphs 1 to 3, the first glass material is BK7.

[0055] BK7 is cheaper to produce than synthetic quartz and has superior processability. BK7 also has a higher refractive index than synthetic quartz. Therefore, it can reduce the cost and size of the coupled optical system, and consequently, the cost and size of the laser irradiation device.

[0056] (Article 5) In the laser light irradiation device described in any one of paragraphs 1 to 4, the multiple laser light sources are multiple laser diodes.

[0057] Therefore, the cost and size of the laser irradiation device can be reduced. (Item 6) In the laser light irradiation apparatus described in any one of items 1 to 5, the second energy gap is greater than twice the photon energy of the laser beam.

[0058] Therefore, even if the laser beam irradiation time is extended, the refractive index of the second lens hardly changes, and the coupling efficiency of the laser beam from the coupling optical system to the optical fiber also hardly changes. Laser beams emitted from each of multiple laser light sources can be stably coupled over a long period of time using optical fibers.

[0059] (Item 7) In the laser light irradiation device described in any one of items 1 to 5, the second energy gap is 1.4 times or more the first energy gap.

[0060] Therefore, even if the laser beam irradiation time is extended, the refractive index of the second lens hardly changes, and the coupling efficiency of the laser beam from the coupling optical system to the optical fiber also hardly changes. Laser beams emitted from each of multiple laser light sources can be stably coupled over a long period of time using optical fibers.

[0061] (Clause 8) In the laser beam irradiation apparatus described in any one of paragraphs 1 to 7, the second power density of the laser beam at the exit surface of the second lens is twice or more the first power density of the laser beam at the incident surface of the first lens.

[0062] Even if the power density of the laser beam in the second lens increases, the refractive index of the second lens hardly changes, and the coupling efficiency of the laser beam from the coupling optical system to the optical fiber also hardly changes. Laser beams emitted from each of multiple laser light sources can be stably coupled over a long period of time using optical fibers.

[0063] (Section 9) In the laser light irradiation apparatus described in any one of paragraphs 1 to 8, the coupling optical system includes a focusing lens. The focusing lens is positioned between the reduction optical system and the optical fiber and is formed of a second glass material.

[0064] Therefore, the laser beams emitted from each of the multiple laser light sources can be coupled to the optical fiber with higher coupling efficiency.

[0065] (Section 10) In the laser light irradiation apparatus described in any one of paragraphs 1 to 9, the coupling optical system includes a plurality of collimating lenses. The plurality of collimating lenses are arranged between a plurality of laser light sources and a reduction optical system and are formed of a first glass material.

[0066] Therefore, the laser beams emitted from each of the multiple laser light sources can be coupled to the optical fiber with higher coupling efficiency.

[0067] (Paragraph 11) A laser processing apparatus according to one embodiment comprises a laser light irradiation device as described in any one of paragraphs 1 to 10.

[0068] In a laser irradiation device, the laser beams emitted from each of multiple laser light sources can be stably coupled over a long period of time using optical fibers. Therefore, with a laser processing device, workpieces can be processed stably over a longer period of time.

[0069] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description and is intended to include all modifications within the meaning and scope of the claims equivalents. [Explanation of Symbols]

[0070] 1,1b,41 Laser beam irradiation device, 2 Laser processing device, 9 Package, 10 Laser light source, 11 Substrate, 12 Lower cladding layer, 13 Active layer, 14 Upper cladding layer, 15,16 Electrodes, 17 Insulating layer, 19,35 Laser beam, 20 Coupling optics, 21 Collimating lens, 22 Reduction optics, 23a,23b Lenses, 23i Incident surface, 23j Exit surface, 24a,24b Lenses, 24i Incident surface, 24j Exit surface, 26 Focusing lens, 30 Optical fiber, 31 Core, 32 Cladding, 40 Workpiece, 42 Irradiation mechanism, 43 Moving mechanism, 44 Workpiece mounting platform, 45 Controller.

Claims

1. It is equipped with multiple laser light sources, each of which emits a laser beam, Optical fiber and The system comprises a coupling optical system positioned between the plurality of laser light sources and the optical fiber, which couples the laser beams to the optical fiber, The aforementioned combined optical system includes a reduction optical system, The reduction optical system includes a first lens and a second lens, In the optical path of the laser beam, the first lens is positioned closer to the plurality of laser light sources than the second lens. The second beam cross-sectional area of ​​the laser beam at the exit surface of the second lens is smaller than the first beam cross-sectional area of ​​the laser beam at the incident surface of the first lens. The first lens is formed of the first glass material, The second lens is formed of a second glass material, A laser light irradiation device wherein the second energy gap of the second glass material is greater than the first energy gap of the first glass material.

2. The laser beam has a wavelength of 380 nm to 550 nm. The first energy gap is 6.6 eV or less. The laser light irradiation apparatus according to claim 1, wherein the second energy gap is greater than 6.6 eV.

3. The laser light irradiation apparatus according to claim 1, wherein the second glass material is synthetic quartz.

4. The laser light irradiation apparatus according to claim 1, wherein the first glass material is BK7.

5. The laser light irradiation device according to claim 1, wherein the plurality of laser light sources are a plurality of laser diodes.

6. The laser light irradiation apparatus according to claim 1, wherein the second energy gap is greater than twice the photon energy of the laser beam.

7. The laser light irradiation apparatus according to claim 1, wherein the second energy gap is 1.4 times or more the first energy gap.

8. The laser light irradiation apparatus according to claim 1, wherein the second power density of the laser beam at the exit surface of the second lens is twice or more the first power density of the laser beam at the incident surface of the first lens.

9. The coupled optical system includes a focusing lens, The laser light irradiation apparatus according to claim 1, wherein the focusing lens is disposed between the reduction optical system and the optical fiber and is made of the second glass material.

10. The aforementioned combined optical system includes a plurality of collimating lenses, The laser light irradiation apparatus according to claim 1, wherein the plurality of collimating lenses are arranged between the plurality of laser light sources and the reduction optical system and are formed of the first glass material.

11. A laser processing apparatus comprising the laser light irradiation device described in claim 1.

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