LASER MODULE AND LASER PROCESSING DEVICE

Abstract

Laser module (10) comprising the following: - a plurality of surface-emitting laser elements (1) made of photonic crystals arranged on a coplanar surface, each of the laser elements (1) being configured to emit a light beam which is a Gaussian single-mode beam; -an arrangement (3) of concave lenses configured to increase the beam width of the light beam emitted by the laser elements (1); - an arrangement (4) of collimator lenses with a plurality of apertures (41) forming collimator lenses to collimate the light rays which have the beam width increased by the arrangement (3) of concave lenses; - a condenser lens (5) configured to focus the light rays collimated by the arrangement (4) of collimator lenses; and - a light guide (6) having an incident end onto which the light rays are incident which are brought together by the condenser lens (5) and an exit end from which the light rays exit, wherein the apertures (41) of the arrangement (4) of collimator lenses are designed to transmit light rays in an energy range of 94.0% to 99.5% inclusive of 100% of the energy of the light rays incident on the arrangement (4) of collimator lenses, or The apertures (41) of the arrangement (4) of collimator lenses each have a dimension in a range from 0.6 times to inclusive 0.85 times a Gaussian beam radius of a light beam incident on each of the apertures (41), wherein the arrangement (3) of concave lenses is arranged immediately after the laser elements (1), wherein the apertures (41) are each arranged in a hexagonal lattice structure corresponding to a hexagonal lattice arrangement of the plurality of laser elements (1).

Description

TECHNICAL FIELD

[0001] The present invention relates to a laser module equipped with a plurality of surface-emitting laser elements, and to a laser processing apparatus using such a laser module. STATE OF THE ART

[0002] Conventional laser modules are equipped with a plurality of laser elements (i.e., semiconductor laser elements), an array of collimator lenses (or a plurality of collimator lenses), a condenser lens, and a light guide. Light beams emitted from the laser elements are collimated by the array of collimator lenses, converged (focused) by the condenser lens, and coupled to the light guide. The output power of the laser module is thus increased by using a plurality of laser elements, resulting in an increase in the brightness of the light beam emitted from the light guide. The laser modules disclosed in Patent Documents 1 and 2 use surface-emitting laser elements as the laser elements.

[0003] Please also refer to Patent Documents 3 to 5. Patent Document 3 relates to an optical system for maintaining the brightness of laser emitters. Patent Document 4 describes a large-area, coherent PCSEL (photonic crystal surface emitting laser) surface emitter. Patent Document 5 describes a laser with a plurality of VCSEL (vertical cavity surface emitting laser) elements arranged in a single chip, thus increasing the laser's power. PRIOR ART DOCUMENTSPatent documents Patent Document 1: JP 2007-248 581 A (lines 1 to 8 and 29 to 31 on page 12 and Fig. 18) Patent Document 2: Japanese Patent JP 2 848 279 B2 (paragraphs

[0010] to

[0012] on page 2 and Fig. 1) Patent document 3: US 2011 / 0 103 056 A1 Patent Document 4: CN 1 03 887 711 A Patent document 5: US 2007 / 0 091 960 A1 SUMMARY OF THE INVENTION Problems to be solved by the invention

[0004] In order to increase the brightness of the light beam emitted from the light guide, it is necessary to increase the convergence of the light beam emitted from the light guide in addition to increasing the output power of the laser module.

[0005] When a plurality of light beams are coupled to a light guide, the convergence of the light beam emitted from the light guide becomes lower when the collimated light beams passing through the array of collimator lenses are not in contact with each other, compared to when the light beams are in contact with each other. Therefore, to increase the convergence of the light beam emitted from the light guide, it is preferable to cause the light beams passing through the array of collimator lenses to be in contact with each other.

[0006] However, in the laser modules disclosed in Patent Documents 1 and 2, the apertures formed in the array of collimator lenses through which the light beams pass are considerably spaced apart for contacting the passing light beams with each other, which reduces the convergence of the light beam emitted from the light guide. However, in Patent Documents 1 and 2, the considerations regarding improving the convergence of the light beam emitted from the light guide are insufficient.

[0007] The present invention aims to solve the problem described above. The object of the present invention is to provide a laser module with a brightness of light beams after they have been emitted from a light guide that is higher than that of conventional lasers. Means to solve the problems

[0008] The object underlying the invention is achieved by a laser module having the features of independent claim 1 and by a laser processing device having the features of independent claim 5. Advantageous developments of the laser module according to the invention are specified in the dependent claims 2 to 4. Effects of the invention

[0009] According to the present invention, a laser module can be provided with a brightness of light beams after being emitted from a light guide that is greater than that of conventional lasers. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The figures show: Fig. 1 is a diagram illustrating a configuration of a laser module according to Embodiment 1 of the present invention; Fig. 2 is a diagram illustrating a plurality of laser elements when viewed from a direction in which light rays are emitted; Fig. 3 is a cross-sectional view illustrating an exemplary structure of a PCSEL element; Fig. Figure 4A is a diagram illustrating the behavior of light inside a layer of photonic crystals; Fig. Figure 4B is a diagram illustrating the behavior of light inside a layer of photonic crystals; Fig. Figure 4C is a diagram illustrating the behavior of light inside a layer of photonic crystals; Fig. Figure 5A is a diagram illustrating the in-plane resonance of light occurring inside a layer of photonic crystals; Fig. Figure 5B is a graph illustrating the emission of light in the direction of the surface normal occurring inside a layer of photonic crystals; Fig. Figure 6A is a diagram showing light rays overlapping at the incident end of a light guide; Fig. 6B an enlarged partial view of Fig. 6A; Fig. 7 is a diagram illustrating a Gaussian-shaped light beam emitted from a light-emitting surface of a laser element; Fig. 8A is a diagram illustrating the beam profile of light rays at the incident end of the light guide; Fig. 8B an enlarged partial view of Fig. 8A; Fig. 9 is a graph for explaining a method for increasing the brightness of light rays at the exit end of the light guide according to Embodiment 1 of the present invention; Fig. 10A is a diagram for explaining an optical simulation according to Embodiment 1 of the present invention; Fig. 10B is a diagram for explaining an optical simulation according to Embodiment 1 of the present invention; Fig. 11 is a graph for explaining a method of increasing the brightness of light beams at the exit end of the light guide according to Embodiment 2 of the present invention; Fig. 12A is a diagram for explaining an optical simulation according to Embodiment 2 of the present invention; Fig. 12B is a diagram for explaining an optical simulation according to Embodiment 2 of the present invention; Fig. 13 is a diagram illustrating a configuration of a laser processing apparatus according to Embodiment 4 of the present invention; Fig. 14 is a diagram illustrating a configuration of a laser module according to Embodiment 5 of the present invention; Fig. 15 is a diagram illustrating a configuration of a laser module according to Embodiment 6 of the present invention. EMBODIMENTS OF THE INVENTION

[0011] Embodiments of the present invention are described below with reference to the drawings. The same or similar features are assigned the same reference numerals in each drawing. Embodiment 1Overall configuration

[0012] Fig. 1 is a diagram illustrating a configuration of a laser module 10 according to Embodiment 1 of the present invention.

[0013] The laser module 10 includes a plurality of laser elements 1, a concave lens array 3, a collimator lens array 4, a condenser lens 5, and a light guide 6, and is configured to couple the light beams (or laser beams) emitted from the laser elements 1 to the light guide 6. The laser module 10 may be mounted on a mounting component (not shown). Although an example in which the laser module 10 is used for material processing (such as cutting or welding metal, glass, carbon fiber reinforced plastic (CFRP), resin, etc.) is described below, the laser module can be used in other applications, such as optical communication.

[0014] In Fig. 1, reference numerals 11, 12, 13, 14, and 15 are assigned to a light beam emitted by the laser element 1 and incident on the concave lens array 3, a light beam that has passed through the concave lens array 3 and is incident on the collimator lens array 4, a light beam that has passed through the collimator lens array 4 and is incident on the condenser lens 5, a light beam that has passed through the condenser lens 5 and is incident on the light guide 6, and a light beam emitted by the light guide 6, respectively. It should be noted that these reference numerals are assigned only formally, and the light beams with the same reference numerals may change in beam width, etc., as they travel.

[0015] The laser elements 1 are mounted on a main surface (a coplanar surface) of a base 2, and each of the laser elements 1 is configured to emit a light beam 11. The laser elements 1 are surface-emitting laser elements that emit light beams in a direction perpendicular to the substrate surface. The laser elements 1 may be photonic crystal surface-emitting lasers (PCSELs), which will be described later.

[0016] The base 2 has a plate-like shape and may include a cooling mechanism for cooling the laser elements and a power supply for supplying current to the laser elements. The laser elements 1 are arranged in a hexagonal lattice structure, as shown in Fig. 2 shown.

[0017] It should be noted that Fig. 2 schematically illustrates the arrangement of laser elements 1 and consequently the shape, number and arrangement pitch of the laser elements 1 are not limited to those shown. While the laser elements 1 in Fig. 2 are shown as having a circular shape, they may also have other shapes, such as a rectangular, a hexagonal, etc. While the laser elements 1 in Fig. 2 are arranged two-dimensionally, they can alternatively also be arranged one-dimensionally.

[0018] The array 3 of concave lenses is arranged immediately after the laser elements 1 and acts to increase the beam width of the light beam 11 emitted by the respective laser elements 1. The array 3 of concave lenses, together with the array 4 of collimator lenses, forms a beam expander. The array 3 of concave lenses has a plurality of concave lenses arranged therein, each corresponding to the respective laser elements 1, so as to coaxially receive the light beam 11 emitted by the respective laser elements 1.

[0019] Regions of the concave lens array 3 that allow the light beams 11 to pass through, thus forming concave lenses, are referred to as apertures 31. The remaining regions, except for the apertures 31 on the concave lens array 3, that do not allow the light beams 11 to pass through while causing diffraction and reflection (hereinafter referred to as diffraction and the like), are referred to as non-aperture regions. The apertures 31 are arranged in a hexagonal lattice structure that corresponds to the hexagonal lattice arrangement of the plurality of laser elements 1.

[0020] In Embodiment 1, it is preferable to arrange the concave lens array 3 in such a way that it is possible to reduce the distance between the laser elements 1 and the collimator lens array 4, thus reducing the size of the laser module 10. However, the concave lens array 3 is not an essential element in this embodiment. Namely, the laser module can be configured such that the light beams 11 emitted by the laser elements 1 are directly incident on the collimator lens array 4.

[0021] When PCSEL elements are to be used as the laser elements 1, it is advantageous to use the concave lens array 3 for the following reason: Surface-emitting lasers made of photonic crystals can be operated to emit light beams with a small divergence angle (i.e., good-quality light beams). This means that the beam width expands to a lesser extent as the light beams propagate.

[0022] In Embodiment 1, the beam width is optimized at the position where the collimator lens array 4 is located, as described later. Increasing the diameter of the light beams emitted by the laser elements 1 by means of the concave lens array 3 allows the beam width to be optimized with a shorter distance from the laser elements 1 to the collimator lens array 4.

[0023] The array 4 of collimator lenses is configured to convert the light beams 12 that have passed through the array 3 of concave lenses into light beams 13 that are parallel (or substantially parallel) to each other. The array 4 of collimator lenses may be an array of convex lenses. The array 4 of collimator lenses is arranged with a plurality of collimator lenses, each corresponding to the respective laser elements 1 (and the apertures 31 of the array 3 of concave lenses), so as to receive the light beam 12 coaxially.

[0024] Regions of the array 4 of collimator lenses that allow the light beam to pass through and thus form collimator lenses are referred to as apertures 41. The remaining regions, with the exception of the apertures on the array 4 of collimator lenses that do not allow the light beam to pass through while causing diffraction and the like, are referred to as non-aperture regions.

[0025] The apertures 31 are arranged in a hexagonal close-packed structure corresponding to the hexagonal lattice arrangement of the plurality of laser elements 1, in a plane. Specifically, the apertures 41 are arranged adjacent to one another. In this example, the distance between the centers of the apertures 41 is equal to twice the radius of the apertures 41 (i.e., the aperture dimension of the array 4 of collimator lenses). The array 4 of collimator lenses is positioned such that the parallel and adjacent light beams 13 that have passed through the apertures 41 are in contact (or substantially in contact) with each other.

[0026] In general, the beam width of a light beam can be defined as half of a width at an intensity distribution at a point where the radiant intensity curve of the light beam reaches a level of 1 / e 2(approximately 13.5%) of a peak value (or a value on the optical axis) in a plane perpendicular to the optical axis. The beam width thus defined may be referred to herein as a Gaussian beam radius. The "beam width" referred to in the embodiments of the present invention is not limited to the dimension thus defined and can be modified according to the desired energy cutoff rate of the light beam.

[0027] The condenser lens 5 is configured such that the plurality of light beams 13 that have passed through the array 4 of collimator lenses are converged (collected) toward the incident end (i.e., the incident end of the core) of the light guide 6. The condenser lens 5 may be a convex lens.

[0028] As mentioned above, the adjacent light beams 13 that have passed through the array 4 of collimator lenses are in contact with each other, so that the adjacent light beams 14 that have passed through the condenser lens 5 are also in contact with each other and are incident on the incident end of the light guide 6. Thus, the convergence of the light beam 15 emitted from the light guide is improved.

[0029] The plurality of light beams 14 incident on the light guide 6 travel through the core of the light guide 6 and are then combined into a single light beam. Thus, a high-power light beam 15 is emitted from the exit end of the light guide 6.

[0030] Since the light beam is transferred outward using the light guide 6, a complex optical system for beam transfer can be omitted, which is advantageous in various applications. Furthermore, the intensity distribution before coupling with the light guide achieves uniformity during the transfer process through the light guide, thus improving beam quality. In particular, the light guide transmission achieves the rotational symmetry of the light beam, which is an important element in two-dimensional laser processing. PCSEL element

[0031] The following describes the PCSEL element, which is an example of laser element 1. The PCSEL element is a surface-emitting type semiconductor laser element. It has a photonic crystal structure with an active layer period close to the optical wavelength, and can emit uniform coherent light. The wavelength of the light beam emitted by a PCSEL element can be controlled by adjusting the semiconductor material used to fabricate the PCSEL element and the period of the photonic crystal structure.

[0032] A specific problem associated with conventional laser diodes is that the transverse mode of an emitted beam changes according to the area of ​​the light-emitting surface, and that the convergence of the light beam decreases with increasing light-emitting surface for increasing output power.

[0033] In contrast, PCSEL elements are known to emit laser light with high power while maintaining high convergence with an increased light-emitting surface area. In the longitudinal mode, PCSEL elements can be operated to emit a light beam with a single wavelength defined by the lattice constant of the photonic crystal, whereas conventional laser diodes can be operated to emit a light beam containing wavelengths within a specific range according to the gain width of the active layer.

[0034] Fig. 3 is a cross-sectional view showing an exemplary structure of a PCSEL element. In Fig. 3, the direction in which the light beam is emitted is defined as the z direction, and the positive side of z is referred to as the front side and the negative side as the back side. GaAs (gallium arsenide) can be used for the material of a stack 100. The PCSEL element includes the stack 100, a window electrode 110 disposed on the surface of the stack 100, a back electrode 120 disposed on the back side of the stack 100, and an AR (anti-reflection) overlay layer 130 disposed in a window formed by the window electrode 110. This window forms an emission surface (a light-emitting surface) for the light beam.

[0035] The stack 100 includes a substrate 101, an n-type cladding layer 102, an active layer 103, a carrier blocking layer 104, a photonic crystal layer 105, a p-type cladding layer 106, and a p-type contact layer 107. The carrier blocking layer 104 is an undoped layer. Holes 105b are formed in the photonic crystal layer 105 in a slab layer, designated by reference numeral 105a. The lattice structure of the photonic crystal layer 105 can have any shape, such as a square shape, a triangular shape, an orthogonal shape, etc.

[0036] In the above-described structure of the PCSEL element, the active layer 103, the carrier blocking layer 104, and the photonic crystal layer 105 may be arranged in the reverse order.

[0037] When a bias voltage is applied across the window electrode 110 and the back electrode 120, the active layer 103 emits light that is modulated by the photonic crystal layer 105 and output in the form of a laser beam in a direction vertical to the substrate surface (a z direction).

[0038] The laser oscillation wavelength is determined by the material and period of the photonic crystal. GaAs, used for the photonic crystal layer 105 of the PCSEL element, has a refractive index of approximately 3.5, while the refractive index in the holes (air) is 1. Considering the volume occupied by the holes 105b (16%) and the stacked structure of the PCSEL element, the effective refractive index near the active layer 103 is approximately 3.3. The period of the photonic crystal is then 980 nm / 3.3 ≈ 295 nm. This period can vary depending on the stacking structure, etc., of the stack 100.

[0039] An exemplary method for manufacturing the PCSEL element (comprising steps S1 to S4) is described in a simple manner. (S1) The n-type cladding layer 102, the active layer 103, the carrier blocking layer 104, and the plate layer 105a are epitaxially grown on the back surface of the substrate 101, for example, by a metal organic chemical vapor deposition (MOCVD) method. (S2) A resist is patterned on the plate layer 105a, and the plate layer 105a is etched, for example, by reactive ion etching (RIE), to form the holes 105b. Thus, the photonic crystal layer 105 is formed. (S3) The p-type cladding layer 106 and the p-type contact layer 107 are epitaxially regrown on the backside of the photonic crystal layer 105, for example, by a metal organic chemical vapor deposition method. (S4) Through a deposition process, the window electrode 110 is disposed on the surface of the p-type cladding layer 102, and the back electrode 120 is disposed on the back of the p-type contact layer 107.

[0040] Referring to the Fig. 4A to 4C and the Fig. 5A and Fig. 5B, which show the behavior of light inside the photonic crystal, the basic idea of ​​how the PCSEL functions as a surface-emitting laser light source is explained. Fig. Figures 4A to 4C are top views of the photonic crystal layer 105. The holes 105b are shown as being in the Fig. 4A to 4C have a true circular shape (or substantially a true circular shape) for illustrative purposes.

[0041] The photonic crystal layer 105 is located near the active layer 103, so it has a restrictive effect on the light generated in the active layer 103. Although the photonic crystal can have any lattice structure, it is shown here as a square shape because this is easy to design. The lattice constant of the photonic crystal is equal to the wavelength λ of the light generated in the active layer 103.

[0042] Assume that light 201 is generated with a wavelength that is Fig. 4A is marked with an arrow. If the photonic crystal has a lattice constant λ, the light 201 is diffracted in directions at 90° or 180°, as in Fig. 4B, and thus diffracted light beams 2021 and 2022 are generated. The diffracted light beams 2021 and 2022 are in turn diffracted in directions at 90° and 180°, as shown in Fig. 4C, and thus diffracted light beams 2031 and 2032 are generated.

[0043] Out of Fig. 4C shows that the diffracted light beams 2021 and 2032, and the diffracted light beams 2022 and 2032, interfere with each other, forming standing waves. Thus, repeated diffraction at 90° and 180°, as well as interference between the diffracted light beams, generate standing waves along the crystal directions inside the photonic crystal. Consequently, the light is trapped in the active layer 103, and light resonance occurs therein.

[0044] Although the Fig. Since Figures 4A to 4C show in-plane diffraction having a photonic crystal formed therein, it is readily understood that constructive interference also occurs in a direction perpendicular to the surface of the photonic crystal. Consequently, the light trapped and resonated in the plane is emitted as a laser beam in the normal direction of the plane.

[0045] Fig. 5A corresponds to Fig. 4C and represents a resonance of light in the plane. Diffracted light beams 301 and 302, which have a difference in optical path equal to twice the wavelength λ, interfere with each other. In the Fig. 4A to 4C, the holes 105b are shown to have an actual circular shape as described, while in Fig. 5A are shown as having a triangular shape.

[0046] It has been found that the beam quality is improved when the holes 105b have a triangular shape compared to when they have a true circular shape. Fig. Figure 5B illustrates the emission of the above-mentioned light in the direction of the surface normal. Diffracted light beams 303 and 304, which have a difference in optical path equal to the wavelength λ, interfere with each other.

[0047] Light beams are emitted from a PCSEL element in both directions of the surface normal (in two directions). In an application where a light beam needs to be emitted in only one direction, the PCSEL element can be configured so that the light beam is emitted only from the front surface due to light reflection from the back electrode 120, as in the PCSEL element described above. Increasing the brightness of the light beam

[0048] If the laser module 10 is to be used for material processing (particularly for a metal cutting process), the light beam for irradiating a workpiece preferably has a high brightness. Accordingly, a method for increasing the brightness of the light beam 15 emitted by the light guide is described below.

[0049] In the following description, P represents L , as in Fig. 1, the arrangement pitch of the laser elements 1, d p represents the aperture dimension (radius) of the laser element 1 in the light-emitting surface, d e represents the aperture dimension (radius) of the arrangement 3 of concave lenses, d c represents the aperture dimension (radius) of the array 4 of collimator lenses, d f represents the core dimension (radius) of the light guide 6 and θ irepresents the convergence angle of the light beam 14.

[0050] The arrangement grid dimension P L of the laser elements 1 is equal to twice (or substantially equal to twice) the aperture dimension d c of the arrangement 4 of collimator lenses. The convergence angle θ i is calculated using the arrangement grid dimension P L expressed by the following equation (1), where N is the number of laser elements 1 arranged on a diagonal line of the hexagonal lattice (see Fig. 2) are positioned, and f is the focal length of the condenser lens 5. θi≈N⋅PL2f

[0051] In one example, the arrangement grid dimension P L approximately equal to 2 mm, the aperture dimension d p is approximately equal to 0.1 mm, the aperture dimensions d e and d care approximately equal to 1 mm, the distance between the laser elements 1 and the array 3 of concave lenses is approximately equal to 10 mm, the focal length (of each concave lens) of the array 3 of concave lenses is approximately equal to 10 mm, the distance between the array 3 of concave lenses and the array 4 of collimator lenses is approximately equal to 40 mm, the focal length (of each collimator lens) of the array 4 of collimator lenses is approximately equal to 50 mm, the distance between the array 4 of collimator lenses and the center of the condenser lens 5 is approximately equal to 10 mm, the focal length f of the condenser lens 5 is approximately equal to 40 mm, and the distance between the center of the condenser lens 5 and the incident end of the light guide 6 is approximately equal to 40 mm. The distance between the arrangement 4 of collimator lenses and the condenser lens 5 preferably has a minimum length, possibly about 0 mm.

[0052] The brightness B oof the light beam 15 at the exit end of the optical fiber is expressed by the following equation (2) assuming that losses are not taken into account, where P0 is the average output power of the light beam 11 emitted by a laser element 1, M is the number of laser elements 1, θ o is the divergence angle of the light beam 15 at the exit end of the light guide and w o the beam width is. B0=M⋅P0π2θo2wo2

[0053] To adjust the brightness B o at the exit end of the light guide, the divergence angle θ o and the beam width w o reduced, which increases the convergence of the light beam.

[0054] The total number M of laser elements 1 can be expressed by using the number N of laser elements 1 on a diagonal line by the following equation (3). M=3N2+14

[0055] When the light guide 6 has a curved portion or the like, the light beam traveling inside the light guide undergoes mode locking within the light guide, so that light incident on the light guide with a low-order mode is emitted from the light guide end, containing a high-order mode. Namely, the light beam is emitted with a maximum allowable divergence angle (NA) of the light guide 6. When the laser module 10 is used for material processing, the light guide 6 has a length of approximately several meters to ten or more meters.

[0056] Although this is short for optical communication applications, the common optical fiber 6 typically has a bent section. Therefore, the divergence angle θ o considered to be equal to (or essentially equal to) an angle sin -1NA, which corresponds to the number of apertures NA, and the beam width w o is considered to be equal to (or substantially equal to) the core diameter d f of the light guide 6. To adjust the brightness B o at the exit end of the light guide, the core diameter d f of the light guide 6 and the number of apertures NA are reduced.

[0057] To determine the core diameter d f of the light guide 6 and the number of apertures NA, it is necessary that the convergence angle θ i of the light beam 14 and the beam width w f at the incident end of the light guide.

[0058] The Fig. 6A and Fig. 6B are diagrams showing the light rays 14 overlapping at the incident end of the light guide. Fig. 6B is an enlarged view of the Fig. 6A, the area outlined with a dashed line. In the drawings, outlines on the upper side with respect to the optical axis of the outlines defining the beam width of the light beams corresponding to those emitted by the respective laser elements 1 are shown by solid lines, and the remaining outlines on the lower side are shown by dashed lines.

[0059] As in the Fig. 6A and Fig. 6B, the light beams 14, each corresponding to that emitted by the respective laser elements 1, overlap at the same position at the incident end of the light guide, so that the beam width of the overlapping light beams is equal to the beam width w f each light beam 14. In the drawings, 2w represents f the beam diameter of the light beam at the incident end of the light guide.

[0060] Here, the beam width wf at the incident end of the optical fiber is expressed by the following equation (4), where w c is the beam width of the light beam 12 incident on the array 4 of collimator lenses, and λ represents the wavelength of the light beam 12. wf={(π⋅wcλ⋅f)2+(1wc)2}−12

[0061] Equation (4) produces values ​​that decrease monotonically in the range expressed by the following equation (5). wc≥λ⋅fπ

[0062] For example, given that λ = 0.94 µm and f = 40 mm, equation (4) produces in the range where w c ≥ 0.11 mm, a monotonically decreasing value, as can be calculated from equation (5). Namely, an increase in the beam width w c at the position of the arrangement 4 of collimator lenses in this area the beam width w f at the incident end of the light guide.

[0063] It is necessary that the maximum light reception angle θ max (= sin -1 NA) of the light guide 6 is equal to the convergence angle θ expressed by equation (1) i or larger than this, while it is necessary that the core diameter d f equal to the beam width w expressed by equation (4) f at the incident end of the light guide or greater than this. However, if θ i and w f are too large, it is considered that the mode coupling occurs inside the light guide 6, as mentioned above, resulting in a reduction of the brightness B o at the exit end of the light guide. The brightness B o has the highest value when the maximum light reception angle θ max of the light guide 6 is equal to the convergence angle θ i and the core diameter d f equal to the beam width w f is.

[0064] By calculating the product of the beam width and the divergence angle of the light beam 15 at the exit end of the optical fiber, the beam parameter product (BPP) is obtained, which more precisely determines the beam quality. The BPP is expressed from equations (1) and (4) by the following equation (6). BPP=θi⋅wfN⋅PL2f{(π⋅wcλ⋅f)2+(1wc)2}−12

[0065] The brightness B i of the light beam 14 at the incident end of the light guide is calculated by the following equation (7). Bi=M⋅P0π2θl2wf2=3N2+1N2P0⋅f2((π⋅wcλ⋅f)2+(1wc)2)π2PL2

[0066] If N in equation (7) is sufficiently larger than 1, the brightness B i at the incident end of the optical fiber is independent of N and is essentially expressed by the following equation (8). Bi=3P0⋅f2((π⋅wcλ⋅f)2+(1wc)2)π2PL2

[0067] As mentioned above, the brightness B oat the exit end of the optical fiber has the highest value when the maximum light reception angle θ max of the light guide 6 is equal to the convergence angle θ i and the core diameter d f equal to the beam width w f If losses inside the light guide 6 are not taken into account, the brightness B o at the exit end of the light guide equal to the brightness B i at the incident end of the light guide. That is, by increasing the brightness B i At the incident end of the light guide, the brightness B o at the exit end of the light guide.

[0068] The brightness B iat the incident end of the light guide, which is expressed by equation (8), increases monotonically in the range expressed by equation (5). However, it should be noted that the proportion of components in the light rays 13 that are incident on the non-aperture regions of the array 4 of collimator lenses and consequently do not pass through the apertures 31 increases, since the aperture dimension d c the arrangement 4 of collimator lenses has a predetermined value when the beam width w c is made too big.

[0069] Consequently, the brightness B i It is possible to change the aperture dimension d c to enlarge to avoid a reduction in brightness B i However, from equation (8) it can be seen that the arrangement pitch P L of the laser elements 1 is then also larger, which increases the brightness B i in any case reduced.

[0070] Thus, it is not preferable to increase the beam width w c easy to enlarge, as this is due to the aperture dimension d c To achieve an optimal beam width w c To determine this, it is necessary to take into account the influence of diffraction and the like produced by the non-aperture regions of the array 4 of collimator lenses.

[0071] Embodiment 1 aims at the concept of increasing brightness B i at the incident end of the light guide, which in turn increases the brightness B o at the exit end of the light guide. This is achieved by the process of optimizing the ratio of the energy of the light beam passing through the apertures 41 to the energy of the light beam 12 incident on the array 4 of collimator lenses (the rate is hereinafter referred to as the energy transfer rate) through an optical simulation.

[0072] The energy transfer rate can be optimized through the process of adjusting the parameters such as the array pitch P L , the aperture dimension d p , the aperture dimension d e , the aperture dimension d c , the distance between the laser elements 1 and the array 3 of concave lenses, the focal length of the array 3 of concave lenses, the distance between the array 3 of concave lenses and the array 4 of collimator lenses, the focal length of the array 4 of collimator lenses and so on.

[0073] Fig. Figure 7 is a diagram illustrating a Gaussian-shaped light beam emitted from the light-emitting surface having the aperture dimension d pof the laser element 1. Reference numeral 11 in the drawing denotes the beam profile of the light beam emitted by the laser element 1, and the arrow indicates the direction in which the light beam 11 is emitted.

[0074] Since the laser element 1 is a surface-emitting laser element, a substantially Gaussian-shaped single-mode light beam 11 with high convergence and high quality can be generated. In particular, with the use of a PCSEL element as the laser element 1, the divergence angle of the light beam 11 can be further reduced, so that the beam width at the position of the concave lens array 3 is sufficiently smaller than the aperture dimension d e can be designed.

[0075] Accordingly, the influence of diffraction, etc., caused by the non-aperture regions of the concave lens array 3 is sufficiently small to be essentially negligible. Thus, the light beam 12 incident on the collimator lens array 4 has a Gaussian (or essentially Gaussian) beam profile.

[0076] The Fig. 8A and Fig. 8B are diagrams illustrating a beam profile of the light beam 14 at the incident end of the light guide. Fig. 8B is an enlarged view of a Fig. 8A with a dashed line. In the Fig. 8A and Fig. 8B is the beam profile showing the beam width w c of 1.6 mm, represented by a solid line, and the beam profile, which represents the beam width w c of 0.8 mm is shown by a dashed line. Fig. 8A and Fig. 8B, a simulation was performed assuming that the aperture dimension d c the arrangement of 4 collimator lenses was equal to 1 mm.

[0077] As in the Fig. 8A and Fig. As shown in Figure 8B, the total intensity when the beam width w c is larger (w c = 1.6 mm: solid line), compared to when the beam width w c is smaller (w c = 0.8 mm: dashed line), due to diffraction, etc., of the light beam at the non-aperture areas of the collimator lens array 4. If the beam width w c larger, the beam profile has a lateral extension, as in Fig. 8B is indicated by an arrow 800, and deviates from an ideal Gaussian shape.

[0078] Fig. 9 is a graphical representation to illustrate a method for increasing the brightness B oof the light beam 15 at the exit end of the light guide according to Embodiment 1 of the present invention. A value on the horizontal axis of the graph represents the ratio (ie, an energy transfer rate) of the energy of the light beam 13 passing through the apertures 41 to the energy of the light beam 12 incident on the collimator lens array 4.

[0079] An increase in the energy transfer rate can be attributed to a reduction in the beam width w c in relation to the aperture dimension d c the arrangement 4 of collimator lenses. A value on the vertical axis of the graph represents the brightness B i of the light beam 14 at the incident end of the light guide.

[0080] To view the graphical representation of Fig. To obtain the results of Figure 9, a simulation was performed assuming that the light beam 12 incident on the collimator lens array 4 has a Gaussian beam profile. However, it should be noted that similar simulation results can be obtained even if the beam profile deviates slightly from the Gaussian shape.

[0081] In general, a complex amplitude distribution u2(x2) obtained after a light beam with a complex amplitude distribution u1(x1) passes through an optical system with a ray matrix ABCD is expressed by the following equation (9), where λ0 is the wavelength of the light beam, a is the calculation range, and L0 is the length of the optical path. u2(x2)=e−jkL01B λ0∫−a+au1(x1)exp[−jπB λ0(A x12−2x1 x2+D x22)]d x1

[0082] The simulation in Fig. 9 was performed using the two-dimensional equation (9). To account for the influence of diffraction, etc., generated by the non-aperture regions on the collimating lens array 4, the complex amplitude distribution u1(x1) was assumed to be a complex Gaussian distribution, and its tails were truncated for the calculations.

[0083] Referring to the Fig. 10A and Fig. 10B, the results of the simulation mentioned above are further explained. Fig. 10A and Fig. 10B illustrate beam profiles of a light beam entering an aperture 41 of the array 4 of collimator lenses and a light beam exiting the aperture 41, respectively.

[0084] Fig. Figure 10A shows that a light beam having a beam width w c which is larger than the aperture dimension d cthe array 4 of collimator lenses, enters the array 4 of collimator lenses. The beam profile of the light beam emitted by the array 4 of collimator lenses differs from the (essentially Gaussian-shaped) beam profile of the light beam entering the array 4 of collimator lenses because the ends of the profile are truncated.

[0085] At Fig. 10A is about the area in the graphical representation of Fig. 9, in which the value of the horizontal axis is not greater than 94.0%. In this example, a lateral tail appears in the beam profile due to a diffraction distribution, and consequently, the beam width of the light beam at the incident end of the light guide is increased (see, for example, arrow 800 in Fig. 8B).

[0086] It can be said that Fig. 9 indicates that when the energy transfer rate (shown on the horizontal axis of the graph) is not higher than 94.0%, the brightness B i of the light beam at the incident end of the light guide is reduced due to a reduction in energy resulting from clipping the ends of the beam profile and due to a diffraction distribution of the beam width.

[0087] Fig. Figure 10B shows, however, that a light beam having a beam width w c which is smaller than the aperture dimension d c the array of 4 collimator lenses, enters the array of 4 collimator lenses. The beam profile of the light beam emitted by the array of 4 collimator lenses is essentially the same as that of the light beam entering the array of 4 collimator lenses, since the ends of the profile are not clipped.

[0088] At Fig. 10B is about the area in the graphical representation of Fig. 9, where the value of the horizontal axis is not less than 99.5%. Here, the light beam enters the downstream condenser lens 5 with a narrow beam width, resulting in an increase in the beam width (the condenser spot diameter) at the incident end of the light guide.

[0089] It can be stated that Fig. 9 indicates that, while the energy transfer rate (a value on the horizontal axis of the graph) of more than 99.5% can minimize a reduction in the energy of the light beam, this cannot sufficiently reduce the beam width at the incident end of the light guide, which reduces the brightness B i of the light beam 14 at the incident end of the light guide.

[0090] It can be seen that the energy transfer rate in the range of 94.0% to 99.5% inclusive has a high brightness B i can achieve. In Fig. 9 shows that when the energy transfer rate is in the range of 94.0% to 99.5% inclusive, a brightness of approximately equal to or greater than 0.8 times the maximum brightness B i with an energy transfer rate of about 97%.

[0091] Whether or not a finished product of a laser module 10 has an energy transfer rate in the range of 94.0% to 99.5% inclusive can be determined by measuring the energy at a position immediately after the array 4 of collimator lenses relative to the energy measured at the position immediately before the array 4 of collimator lenses, which is assumed to be 100%. The energy of the light beam can be measured, for example, using a laser power meter that utilizes piezoelectric conversion.

[0092] As shown above, an increase in the energy transfer rate, which is defined by the horizontal axis of Fig. 9, leads to a reduction of the beam width w c at the position of the array 4 of collimator lenses. The energy transfer rate, which is higher than 99.5%, leads to the monotonically increasing range of brightness B i(at the incident end of the light guide), which is expressed by equation (5), falling beam width w c , which means that the brightness B i , which is expressed by equation (8), decreases in this region.

[0093] On the other hand, a reduction in the energy transfer rate, which is defined by the horizontal axis of Fig. 9, leads to an increase in the beam width w c at the position of the array 4 of collimator lenses. The energy transfer rate, which is, for example, less than 94%, leads to the beam width w f at the incident end of the light guide, which has an increased value due to the influence of diffraction, etc., generated by the non-aperture areas on the collimator lens array 4. This means that the brightness B i which is expressed by equation (8).

[0094] To adjust the brightness B i and B oTo increase the energy transfer rate, it is preferable that the energy transfer rate be higher. However, technically, it is impossible to achieve an energy transfer rate of 100% due to losses due to diffraction and the like caused by the non-aperture regions on the collimator lens array 4. When the energy of the light beam 13 that has passed through the apertures 41 is considered to be 100%, the laser module 10 according to Embodiment 1 is adjusted to allow a light beam of approximately 98% of the energy to be incident on the light guide 6.

[0095] If the energy of the light beam 12 entering the array 4 of collimator lenses is considered to be 100%, and a light beam with an energy of 94% has passed through the apertures 41, about 92% or more of the energy of the light beam 12 can be incident on the light guide 6 and used.

[0096] According to embodiment 1, a light beam having an energy in the range of 94% to 99.5% inclusive with respect to the energy of the light beam 12 entering the array 4 of collimator lenses, which is assumed to be 100%, has passed through the apertures 41, wherein the brightness B o of the light beam 15 at the exit end of the light guide, which consequently makes it possible to obtain a laser module 10 suitable for material processing. Embodiment 2

[0097] Fig. 11 is a graphical representation to illustrate a method for increasing the brightness B o of the light beam 15 at the exit end of the light guide according to Embodiment 2 of the present invention. A value on the horizontal axis of the graph represents the ratio w c / d c the beam width (the Gaussian beam radius) w cat the position of the arrangement 4 of collimator lenses to the aperture dimension d c of the arrangement 4 of collimator lenses. A value on the vertical axis of the graph represents the brightness B i of the light beam 14 at the incident end of the light guide.

[0098] As described, Embodiment 1 involves optimizing the ratio (ie, the energy transfer rate) of the energy of the light beam passing through the apertures 41 to the energy of the light beam 12 entering the array 4 of collimator lenses via an optical simulation. In Embodiment 2, the brightness B i at the entrance end of the light guide, which in turn increases the brightness B o at the exit end of the light guide by increasing the ratio w c / d c, referred to above, is optimized using the same optical simulation. Embodiment 2 differs from Embodiment 1 only in the target to be optimized and shares the same basic structure as Embodiment 1.

[0099] Referring to the Fig. 12A and Fig. 12B, the simulation results for embodiment 2 are further explained. Fig. 12A and Fig. 12B correspond to the Fig. 10A and Fig. 10B and 10C illustrate beam profiles of a light beam 12 entering an aperture 41 in the collimator lens array 4 and a light beam 13 exiting the aperture 41.

[0100] In Fig. 12A enters a light beam having the same beam width (the Gaussian beam radius) as that of the aperture dimension d cof the array 4 of collimator lenses, into the array 4 of collimator lenses. The beam profile of the light beam emitted by the array 4 of collimator lenses thus differs from the (essentially Gaussian-shaped) beam profile of the light beam entering the array 4 of collimator lenses because the ends of the profile are truncated.

[0101] Fig. 12 shows that the value of the horizontal axis in the graphical representation of Fig. 11 is equal to 1.0. Since the beam profile has a lateral extension due to a diffraction distribution, the beam width of the light beam is increased at the incident end of the light guide (see, for example, arrow 800 in Fig. 8B).

[0102] It can be stated that Fig. 11 indicates that if the ratio w c / d c(a value on the horizontal axis of the graph) is larger (ie closer to 1.0), the brightness B i of the light beam 14 at the incident end of the light guide due to an energy decrease resulting from the beam profile in which the end is clipped and due to a diffraction distribution of the beam width.

[0103] Meanwhile, in Fig. 12B a light beam with a beam width w c which is smaller than the aperture dimension d c the array 4 of collimator lenses, into the array 4 of collimator lenses. The beam profile of the light beam emitted by the array 4 of collimator lenses is essentially the same as the beam profile of the light beam entering the array 4 of collimator lenses, since the profile has remaining ends without these being cut off. Fig. 12B, the light beam enters the condenser lens 5 with a smaller beam width, which consequently increases the beam width (ie the condenser spot diameter) at the incident end of the light guide.

[0104] In Embodiment 1, with reference to the Fig. 10A and Fig. 10B Conditions for achieving high brightness B i (ie the energy transfer rate is discussed, which is in the range of 94.0% to 99.5% inclusive). Fig. 9 found that under such conditions a brightness of about 0.8 times or more of the maximum brightness B i can be achieved. In the same way, in embodiment 2, the range of the ratio w c / d c (from 0.60 to 0.85 inclusive) in Fig. 11 as a condition for obtaining a large brightness B iprovided that a brightness of approximately 0.8 times or more of the maximum brightness B i in the range of the ratio w c / d c can be achieved.

[0105] Whether or not a finished product of a laser module 10 has a ratio w c / d c (from 0.60 to 0.85 inclusive) can be determined by measuring the beam width at a position immediately in front of the array 4 of collimator lenses, for example using a CCD camera type laser beam profile measuring device.

[0106] According to embodiment 2, the brightness B o of the light beam 15 at the exit end of the light guide can be increased in a similar manner, which in turn makes it possible to obtain a laser module 10 suitable for material processing. Embodiment 3

[0107] In embodiment 3, various parameters (the arrangement pitch P L of the laser elements 1, the aperture dimension d p on the light-emitting surface of the laser elements 1, the aperture dimension d e the arrangement 3 of concave lenses, the aperture dimension d c the array 4 of collimator lenses, the distance between the laser elements 1 and the array 3 of concave lenses, the focal length of the array 3 of concave lenses, the distance between the array 3 of concave lenses and the array 4 of collimator lenses, the focal length of the array 4 of collimator lenses, and so on) are set so that the value of the element C is zero in a beam matrix expressed by the following equation (10) defined in a range from the laser elements 1 to the condenser lens 5. (ABCD)

[0108] Light rays emitted by the (surface-emitting) laser elements 1 are essentially plane waves emerging perpendicularly from the substrate surface. Therefore, when the element C of the beam matrix, expressed by equation (10), is zero, the light rays propagate while maintaining their orientations.

[0109] Even if there are, for example, slight deviations (caused, for example, by manufacturing tolerances) regarding the positions of the laser elements 1 or between the positions and the aperture dimensions d e and d c of the lens arrangements 3 and 4, the light beams emitted by all the laser elements 1 can be input perpendicularly into the condenser lens 5.

[0110] In Embodiment 3, the focal length f of the condenser lens 5 is designed to be equal to the distance from the condenser lens 5 to the incident end of the light guide 6. Thus, the light beams emitted from the respective laser elements 1 are converged (converged) at the same (or substantially the same) position at the incident end of the light guide 6.

[0111] Even if there are, for example, small deviations (caused, for example, by manufacturing tolerances) regarding the positions of the laser elements 1 or between the positions and the aperture dimensions d e and d cof the lens arrangements 3 and 4, the light beams emitted by all the laser elements 1 can therefore be converged (focused) at the same (or substantially the same) position of the condenser lens 5, which enables smoother alignment of various optical elements 1 and 3 to 5.

[0112] In particular, when a PCSEL element is used as the laser element 1, the light beam is emitted which is a plane wave with a high quality, so that the aperture dimension d p at the light-emitting surface is further magnified. The position spaced from the condenser lens 5 by a distance equal to the focal length f of the condenser lens 5 is the condenser spot position, so that the core diameter d f of the light guide 6 is reduced. Embodiment 4

[0113] Fig. 13 is a diagram illustrating a configuration of a laser processing apparatus according to Embodiment 4 of the present invention. The laser processing apparatus 1000 includes a laser module 10 according to any one of Embodiments 1 to 3 or a laser module 10 having any combination of features derived from Embodiments 1 to 3, and a processing head 50 for irradiating a workpiece with the light beam 15 output from the light guide 6.

[0114] The machining head 50 is a hollow tubular member and is provided with two machining lenses 51 and 52 therein, which make light beams parallel and converging to form a light spot at a machining point on the workpiece W. The distal end of the machining head 50 is formed in a nozzle shape, allowing the light beams converged (condensed) by the machining lens 52 to pass therethrough and supplying a processing gas toward the workpiece W.

[0115] According to Embodiment 4, with the laser module 10 having a brightness of the light beam 15 emitted from the light guide that is higher than that of conventional lasers, a laser processing apparatus 1000 with higher processing precision can be obtained. Embodiment 5

[0116] Fig. Figure 14 is a diagram illustrating a configuration of a laser module according to Embodiment 5 of the present invention. In Embodiments 1 to 3, the concave lens array 3 and the collimator lens array 4 together constitute the beam expander. In Embodiment 5, as shown in Fig. 14, an array 23 of convex lenses is arranged in place of the array 3 of concave lenses, and this array 23 of convex lenses and an array 24 of collimator lenses together form the beam expander. The array 23 of convex lenses and the array 24 of collimator lenses are arranged such that the convergence point is formed between the two arrays 23 and 24 of lenses.

[0117] The arrangement 23 of convex lenses has apertures 231 corresponding to the apertures 31 of the arrangement 3 of concave lenses arranged in Fig. 1. The array 24 of collimator lenses has apertures 241 corresponding to the apertures 41 of the array 4 of collimator lenses shown in Fig. 1 are shown.

[0118] The laser module 10 according to Embodiment 4 has the same components as those of Embodiments 1 to 3 except for the beam expander. For a description of the features of Embodiment 5 in Fig. 14, the same reference numerals as those used in Embodiments 1 to 3 are used.

[0119] According to Embodiment 5, with the beam expander different from that of Embodiments 1 to 3, the same advantages as those of Embodiments 1 to 3 are achieved. Embodiment 6

[0120] Fig. Figure 15 is a diagram illustrating a configuration of a laser module according to Embodiment 6 of the present invention. In Embodiment 5, two sets of lens arrays, the convex lens array 23 and the collimator lens array 24, together constitute the beam expander. In Embodiment 6, as shown in Fig. 15, a further array 35 of convex lenses is arranged between an array 33 of convex lenses and an array 34 of collimator lenses, and these three sets of lens arrays together form the beam expander.

[0121] The convex lens arrays 33 and 35 are arranged such that the convergence point is formed between the two lens arrays 33 and 35. The convex lens array 35 and the collimator lens array 34 are arranged such that the convergence point is formed between the two lens arrays 34 and 35.

[0122] The arrangement 33 of convex lenses has apertures 331 which correspond to the apertures 31 of the arrangement 3 of concave lenses which are arranged in Fig. 1. The array 34 of collimator lenses has apertures 341 corresponding to the apertures 41 of the array 4 of collimator lenses shown in Fig. 1 are shown.

[0123] The laser module 10 according to Embodiment 6 has the same components as those of Embodiments 1 to 3 and 5 except for the beam expander. The same reference numerals as those used in Embodiments 1 to 3 and 5 will be used for a description of Embodiment 6 and in Fig. 15 used.

[0124] According to Embodiment 6, with the beam expander different from that of Embodiments 1 to 3 and 5, similar advantages to those achieved by Embodiments 1 to 3 and 5 are achieved.

[0125] In embodiment 3, various parameters (the arrangement pitch P L of the laser elements 1, the aperture dimension d p on the light-emitting surface of the laser elements 1, the aperture dimension d e the arrangement 3 of concave lenses, the aperture dimension d cThe values ​​of the various parameters (e.g., the distance between the laser elements 1 and the concave lens array 3, the focal length of the concave lens array 3, the distance between the concave lens array 3 and the collimator lens array 4, the focal length of the collimator lens array 4, and so on) are set such that the value of the element C in the beam matrix expressed by equation (10) defined in a range from the laser elements 1 to the condenser lens 5 is zero. In embodiment 6, instead of or in addition to this, the various parameters are set such that the element B is zero.

[0126] When the element B is zero, even if the divergence angle of the light beam emitted from the laser elements 1 deviates from the designed value, a desired beam width and a desired divergence angle at the position of the condenser lens 5 can be easily achieved merely by adjusting the distance between the three sets of lens arrangements described above.

[0127] While the present invention has been described with reference to the above embodiments, the scope of the present invention is not limited to these embodiments. Further embodiments can be configured by any combination of the features of various embodiments. A variety of modifications and improvements can be added to the above embodiments, meaning that numerous variations of the present invention exist. LIST OF REFERENCE SYMBOLS 1 laser element 2 Base 3 Arrangement of concave lenses 4 Arrangement of collimator lenses 5 Condenser lens 6 light guides 10 laser modules 50 machining heads 1000 laser processing device P L Arrangement grid dimension of the laser elements d p Aperture dimension on the light-emitting surface of the laser elements d e Aperture dimension of the arrangement of concave lenses d c Aperture dimension of the arrangement of collimator lenses θ i Convergence angle of a light beam d f Core diameter of the light guide

Claims

[1] Laser module (10) comprising: - a plurality of surface-emitting laser elements (1) made of photonic crystals arranged on a coplanar surface, each of the laser elements (1) being configured to emit a light beam which is a Gaussian-shaped single-mode beam; -an array (3) of concave lenses configured to increase the beam width of the light beam emitted by the laser elements (1); - an array (4) of collimator lenses having a plurality of apertures (41) forming collimator lenses for collimating the light beams having the beam width increased by the array (3) of concave lenses; - a condenser lens (5) configured to combine the light rays collimated by the array (4) of collimator lenses; and - a light guide (6) having an incident end onto which the light rays converged by the condenser lens (5) are incident, and an exit end from which the light rays emerge, wherein the apertures (41) of the arrangement (4) of collimator lenses are designed to transmit light rays in an energy range of 94.0% up to and including 99.5% of 100% energy of the light rays incident on the arrangement (4) of collimator lenses, or the apertures (41) of the array (4) of collimator lenses each have a dimension in a range from 0.6 times up to and including 0.85 times a Gaussian beam radius of a light beam incident on each of the apertures (41), the array (3) of concave lenses being arranged immediately after the laser elements (1), the apertures (41) each being arranged in a hexagonal lattice structure corresponding to a hexagonal lattice arrangement of the plurality of laser elements (1). [2] Laser module (10) according to claim 1, wherein - the apertures (41) of the arrangement (4) of collimator lenses are arranged adjacent to one another and - the surface-emitting laser elements (1) made of photonic crystals with a pitch (P L ) which is twice as large as the dimension of each of the apertures (41) of the array (4) of collimator lenses. [3] Laser module (10) according to claim 1 or 2, wherein in a beam matrix expressed by the following expression, which is defined in a range from the plurality of surface-emitting laser elements (1) made of photonic crystals to the condenser lens (5), an element C is equal to zero and wherein a focal length of the condenser lens (5) is equal to a distance from the center of the condenser lens (5) to the incident end of the light guide (6). (ABCD) [4] Laser module (10) according to claim 3, wherein the element B in the beam matrix is zero. [5] Laser processing device (1000) comprising: - a laser module (10) according to one of claims 1 to 4; and - a processing head (50) for irradiating a workpiece (W) with a light beam emitted from the light guide (6) towards a workpiece (W).

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