Light source module, processing machine, and processing method

Abstract

A light source module (1) which emits combined wave laser light is provided with: a plurality of semiconductor laser elements (6); and a control circuit (50) for controlling power of laser light emitted from each of the plurality of semiconductor laser elements (6). The plurality of semiconductor laser elements (6) include a first element group (10) for emitting first laser light and a second element group (20) for emitting second laser light. The combined laser light includes at least one of the first laser light and the second laser light. The control circuit (50) maintains a combined wave wavelength, which is an average wavelength of the combined laser light, to be constant with respect to a change of the power of the combined laser light. In the case where the power of the first laser light and the power of the second laser light are equal, an average wavelength of the first laser light is longer than that of the second laser light.

Description

[Technical field]

[0001] The present disclosure relates to a light source module, a processing machine, and a processing method. [Background technology]

[0002] Conventionally, laser light has been used for processing purposes, and a high-output and highly efficient laser light source is required. A semiconductor laser element is used as such a laser light source.

[0003] In processing applications, the output of the laser light may be changed, and when the power of the laser light is changed in a semiconductor laser element, the wavelength of the laser light also changes. When the laser light emitted by such a semiconductor laser element is irradiated onto a material to be processed, the absorptivity of the laser light may change depending on the wavelength of the laser light. Here, the optical absorption spectrum of the material to be processed will be described with reference to FIG. 13. FIG. 13 is a graph showing the optical absorption spectrum of metals. FIG. 13 shows the optical absorption spectra of seven types of metals, including Cu, at wavelengths of 400 nm or more and 1200 nm or less. The horizontal axis of the graph in FIG. 13 indicates the wavelength, and the vertical axis indicates the absorptivity. As shown in FIG. 13, for example, the absorptivity of Cu is about 65% when the wavelength is about 450 nm, whereas it is about 5% when the wavelength is about 1070 nm. Also, as shown in FIG. 13, the optical absorption spectrum differs for each material.

[0004] In this way, the absorption rate of the laser light in the processing object depends on the wavelength and the material. Therefore, if the wavelength of the laser light varies depending on the power, this becomes a problem, especially when processing a composite material in which multiple materials are combined. In other words, when irradiating a composite material with a laser light, if the power of the laser light is a predetermined value, the composite material will melt uniformly, but if the power of the laser light is changed from the predetermined value, a situation may occur in which only a portion of a specific material in the composite material melts and the other materials do not melt.

[0005] As a technique for solving such problems, for example, Patent Document 1 describes a light source module that monitors the wavelength of laser light emitted by a semiconductor laser element and controls the temperature of the semiconductor laser element so that the wavelength is constant. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2000-164977 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the light source module described in Patent Document 1 requires the use of a wavelength monitor, a heating and cooling element, and the like to control the temperature of the semiconductor laser element, resulting in a complex configuration.

[0008] The present disclosure is intended to solve such problems, and aims to provide a light source module and the like that has a simplified configuration and is capable of emitting laser light with reduced power dependence of the average wavelength. [Means for solving the problem]

[0009] In order to solve the above problems, one aspect of the light source module according to the present disclosure is a light source module that emits a combined laser beam, comprising: a plurality of semiconductor laser elements; and a control circuit that controls a power of laser beam emitted by each of the plurality of semiconductor laser elements, wherein the plurality of semiconductor laser elements include a first element group that includes one or more first semiconductor laser elements and emits a first laser beam; and a second element group that includes one or more second semiconductor laser elements and emits a second laser beam, wherein the combined laser beam includes at least one of the first laser beam and the second laser beam, and the control circuit controls the power of each of the first laser beam and the second laser beam to maintain a combined wavelength, which is an average wavelength of the combined laser beam, constant against changes in the power of the combined laser beam, and wherein when the power of the first laser beam and the power of the second laser beam are equal, the average wavelength of the first laser beam is longer than the average wavelength of the second laser beam.

[0010] In this way, the combined laser light output by the light source module according to the present disclosure includes at least one of the first laser light and the second laser light. Therefore, even if the average wavelength of the first laser light becomes longer as the power of the first laser light increases, the power of the second laser light, which has a shorter average wavelength than the first laser light, can be increased to reduce the power dependency of the average wavelength of the combined laser light. In addition, the light source module according to the present disclosure does not require a wavelength monitor or the like used in the light source module described in Patent Document 1, and therefore has a simpler configuration than the light source module described in Patent Document 1.

[0011] In addition, in one aspect of the light source module according to the present disclosure, a power of the first laser light may be equal to or greater than a power of the second laser light.

[0012] In this manner, by maintaining the relationship between the power of the first laser beam and the power of the second laser beam, it is possible to maintain the average wavelength of the combined laser beam constant.

[0013] In addition, in one aspect of the light source module according to the present disclosure, the one or more first semiconductor laser elements may include a plurality of first semiconductor laser elements, each of which emits laser light of the same wavelength.

[0014] In this manner, by the first element group including a plurality of semiconductor laser elements, the power of the first laser light can be increased.

[0015] In addition, in one aspect of the light source module according to the present disclosure, the plurality of first semiconductor laser elements may be connected in series.

[0016] In this way, by connecting a plurality of first semiconductor laser elements in series, the amount of current required to drive the light source module can be reduced compared to the case of connecting them in parallel, and therefore the power supply required to drive the light source module can be made smaller.

[0017] Furthermore, in one aspect of the light source module according to the present disclosure, when the power of the combined laser light is a first power, the average wavelength of the first laser light is λ11, the average wavelength of the combined laser light is λt1, and when the power of the combined laser light is a second power greater than the first power, the average wavelength of the first laser light is λ12, and the average wavelength of the combined laser light is λt2, then λ12-λ11>λt2-λt1 may hold.

[0018] In the light source module according to the present disclosure, when the power of the combined laser light increases from the first power to the second power, the average wavelength of the first laser light and the average wavelength of the combined laser light may become longer as the power of the first laser light included in the combined laser light increases. In such a case, by combining the combined laser light with a second laser light having an average wavelength shorter than that of the first laser light, at least a part of the longer wavelength of the combined laser light can be offset. In other words, the power dependency of the average wavelength of the combined laser light can be reduced by using the second laser light.

[0019] In addition, in one aspect of the light source module according to the present disclosure, an average wavelength of the combined laser light when all of the plurality of semiconductor laser elements operate at their maximum rated output may be equal to an average wavelength of the first laser light at its minimum laser output.

[0020] This makes it possible to maintain the average wavelength constant over the entire range from the minimum power to the maximum rated power (i.e., the power at the maximum rated output) of the combined laser light that can be emitted by the light source module, by setting the average wavelength of the combined laser light to the average wavelength of the first laser light at the minimum power (or the average wavelength of the combined laser light when all of the multiple semiconductor laser elements are operating at the maximum rated output).

[0021] In addition, when the power of the first laser light is close to the minimum power, the average wavelength of the first laser light is likely to fluctuate due to temperature changes, etc. When the first laser light and the second laser light are included in the combined laser light with a power close to the minimum power, the power of the first laser light is smaller than when only the first laser light is included in the combined laser light, making it difficult to stabilize the average wavelength of the first laser light. In this case, the power of the second laser light is also approximately equal to or less than the power of the first laser light, making it difficult to stabilize the average wavelength of the second laser light. In other words, by making the combined laser light with a power close to the minimum power include only the first laser light, the average wavelength of the combined laser light can be stabilized. Here, as in the light source module 1 according to the present embodiment, the average wavelength at the minimum power of the first laser light and the average wavelength of the first laser light and the second laser light are Maximum ratingWhen the average wavelength of the combined laser beam at the time of output coincides with that of the first laser beam, it is possible to maintain the average wavelength of the combined laser beam at the average wavelength at the minimum power of the first laser beam over the entire range from the minimum power of the combined laser beam to the maximum rated power. In this way, when the average wavelength of the combined laser beam is maintained at the average wavelength at the minimum power of the first laser beam, when the power of the combined laser beam is close to the minimum power, the combined laser beam contains only the first laser beam. Therefore, it is possible to stabilize the average wavelength of the combined laser beam when it is close to the minimum power.

[0022] In one aspect of the light source module according to the present disclosure, an average wavelength of the first laser light at maximum rated power may be longer than an average wavelength at minimum power by 5 nm or more.

[0023] In this way, even if the average wavelength of the first laser beam changes by 5 nm or more depending on the power, the average wavelength of the combined laser beam can be kept constant by appropriately controlling the power of the second laser beam.

[0024] In addition, in one aspect of the light source module according to the present disclosure, the control circuit may control the power of the laser light of each of the plurality of semiconductor laser elements so that the combined wavelength matches an average wavelength of the combined laser light when all of the plurality of semiconductor laser elements operate at their maximum rated output.

[0025] This makes it possible to maintain the average wavelength of the combined laser beam constant within a range including the maximum rated power of the combined laser beam that can be emitted by the light source module, thereby realizing a light source module capable of emitting a high-power combined laser beam.

[0026] In addition, in one aspect of the light source module according to the present disclosure, the one or more first semiconductor laser elements and the one or more second semiconductor laser elements may include a nitride-based semiconductor.

[0027] This makes it possible to emit blue laser light, and thus makes it possible to realize a light source module capable of emitting laser light capable of processing metals such as Cu and Au.

[0028] In order to solve the above problem, one aspect of a processing machine according to the present disclosure includes the above light source module.

[0029] This allows the emission of laser light with reduced power dependency of the average wavelength, making it possible to easily process composite materials made of a combination of multiple materials. In addition, the processing machine according to the present disclosure does not require a wavelength monitor or the like used in the light source module described in Patent Document 1, and therefore has a simplified configuration.

[0030] In addition, in order to solve the above-mentioned problems, one aspect of the processing method according to the present disclosure is a processing method for processing a material using a combined laser beam emitted from a light source module, the light source module includes a plurality of semiconductor laser elements, the plurality of semiconductor laser elements include a first element group including one or more first semiconductor laser elements and emitting a first laser beam, and a second element group including one or more second semiconductor laser elements and emitting a second laser beam, the combined laser beam includes at least one of the first laser beam and the second laser beam, the processing method includes a control step of controlling the power of each of the first laser beam and the second laser beam to maintain a combined wavelength, which is an average wavelength of the combined laser beam, constant against changes in the power of the combined laser beam, and when the power of the first laser beam and the power of the second laser beam are equal, the average wavelength of the first laser beam is longer than the average wavelength of the second laser beam.

[0031] This makes it possible to emit laser light with reduced power dependence of the average wavelength, making it easy to process composite materials made up of multiple materials.

[0032] In one embodiment of the processing method according to the present disclosure, the material may contain Au or Cu.

[0033] Although the wavelength dependency of the absorptance of Au and Cu is relatively large, the processing method according to the present disclosure reduces the power dependency of the average wavelength when processing such materials, so that stable processing is possible even when the power is changed. In addition, laser light with a wavelength (about 450 nm) with high absorptance in Au and Cu can be generated by using, for example, semiconductor laser elements including nitride-based semiconductors as the multiple semiconductor laser elements.

[0034] In addition, in one aspect of the processing method according to the present disclosure, in the control step, the combined laser light may be irradiated onto the material while changing a power of the combined laser light.

[0035] In this way, even if processing is performed while varying the power of the combined laser beam, the fluctuation in the average wavelength of the combined laser beam is reduced, so that stable processing is possible. Effect of the Invention

[0036] According to the present disclosure, it is possible to provide a light source module or the like that has a simplified configuration and is capable of emitting laser light with reduced power dependency of the average wavelength. [Brief description of the drawings]

[0037] [Figure 1] FIG. 1 is a block diagram showing a functional configuration of a light source module and a processing machine according to the first embodiment. [Diagram 2] FIG. 2 is a graph showing the relationship between the power and the average wavelength of the first laser light and the second laser light of the light source module according to the first embodiment. [Diagram 3] FIG. 3 is a table showing the relationship between the power of the combined laser light, the first laser light, and the second laser light of the light source module according to the first embodiment. [Figure 4A] FIG. 4A is a graph showing the light intensity spectrum of combined laser light at an operating point 1 of the light source module according to the first embodiment. [Figure 4B]FIG. 4B is a graph showing the light intensity spectrum of the combined laser light at the operating point 2 of the light source module according to the first embodiment. [Figure 4C] FIG. 4C is a graph showing the light intensity spectrum of the combined laser light at the operating point 3 of the light source module according to the first embodiment. [Figure 4D] FIG. 4D is a graph showing the light intensity spectrum of the combined laser light at operating point 4 of the light source module according to the first embodiment. [Diagram 5] FIG. 5 is a flowchart showing control steps included in the processing method using the processing machine according to the first embodiment. [Figure 6A] FIG. 6A is a schematic graph showing the relationship between the intensity distribution of a combined laser beam and the absorption coefficient of a material to be processed when the range of wavelengths contained in the combined laser beam is narrow. [Figure 6B] FIG. 6B is a schematic graph showing the relationship between the intensity distribution of the combined laser beam and the absorption coefficient of the material to be processed when the combined laser beam contains a wide range of wavelengths. [Figure 7] FIG. 7 is a block diagram showing a functional configuration of the light source module according to the second embodiment. [Figure 8] FIG. 8 is a graph showing the relationship between the power and the average wavelength of the first laser light, the second laser light, and the third laser light of the light source module according to the second embodiment. [Figure 9] FIG. 9 is a table showing the relationship between the power of the combined laser light, the first laser light, the second laser light, and the third laser light of the light source module according to the second embodiment. [Figure 10A] FIG. 10A is a graph showing the light intensity spectrum of combined laser light at an operating point 1 of the light source module according to the second embodiment. [Figure 10B] FIG. 10B is a graph showing the light intensity spectrum of the combined laser light at the operating point 2 of the light source module according to the second embodiment. [Figure 10C] FIG. 10C is a graph showing the light intensity spectrum of the combined laser light at the operating point 3 of the light source module according to the second embodiment. [Figure 10D] FIG. 10D is a graph showing the light intensity spectrum of the combined laser light at the operating point 4 of the light source module according to the second embodiment. [Figure 10E] FIG. 10E is a graph showing the light intensity spectrum of the combined laser light at operating point 5 of the light source module according to the second embodiment. [Figure 11] FIG. 11 is a perspective view showing a configuration of a light source module according to the third embodiment. [Figure 12] FIG. 12 is a perspective view showing a configuration of a light source module according to the fourth embodiment. [Figure 13] FIG. 13 is a graph showing the optical absorption spectrum of a metal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, and the arrangement and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0039] In addition, each figure is a schematic diagram and is not necessarily illustrated precisely. Therefore, the scales and the like are not necessarily the same in each figure. In addition, in each figure, the same reference numerals are given to substantially the same configurations, and duplicated explanations are omitted or simplified.

[0040] (Embodiment 1) A light source module, a processing machine, and a processing method according to the first embodiment will be described.

[0041] [1-1. Overall composition] First, the overall configuration of a light source module and a processing machine according to the present embodiment will be described with reference to Fig. 1. Fig. 1 is a block diagram showing the functional configuration of a light source module 1 and a processing machine 2 according to the present embodiment.

[0042] As shown in FIG. 1, the processing machine 2 is a laser processing machine equipped with a light source module 1, and irradiates a material or the like that is an irradiation target with a combined laser light that is a laser light emitted by the light source module 1. In this embodiment, the processing machine 2 further includes a light guide unit 70 that guides the combined laser light emitted by the light source module 1 to the irradiation target. The light guide unit 70 is not particularly limited, but includes, for example, an optical component for light guide such as an optical fiber or a mirror, and an optical component for adjusting a laser diameter such as a lens. In addition, the processing machine 2 (or the light source module 1) may include an input means for inputting parameters such as the power of the combined laser light from the outside. For example, the processing machine 2 may include a keyboard, a touch panel, or the like as the input means.

[0043] 1, the light source module 1 includes a plurality of semiconductor laser elements 6 and a control circuit 50. In this embodiment, the light source module 1 further includes a beam-combining optical system 60.

[0044] The semiconductor laser elements 6 are light sources of the light source module 1, and include a first element group 10 including one or more first semiconductor laser elements and emitting a first laser light, and a second element group 20 including one or more second semiconductor laser elements and emitting a second laser light. Therefore, the combined laser light emitted by the light source module 1 includes at least one of the first laser light and the second laser light. The first semiconductor laser element included in the first element group 10 and the second semiconductor laser element included in the second element group 20 have different wavelengths of emitted laser light. When the power of the first laser light and the power of the second laser light are equal, the average wavelength of the first laser light is longer than the average wavelength of the second laser light. In addition, the average wavelength of the first laser light is equal to or greater than the average wavelength of the combined laser light, and the average wavelength of the second laser light is equal to or less than the average wavelength of the combined laser light. In this embodiment, each of the semiconductor laser elements 6 includes a nitride-based semiconductor, and is made of In x Ga 1-xIt has an active layer containing N(0 < x < 1). As a result, since it becomes possible to emit blue laser light, for example, a light source module 1 capable of emitting laser light that can process metals such as Cu and Au can be realized.

[0045] The wavelength of the laser light emitted by each of the first semiconductor laser element and the second semiconductor laser element can be adjusted, for example, by adjusting the composition ratio of In contained in the active layer. Specifically, by making the composition ratio of In contained in the active layer of the first semiconductor laser element larger than the composition ratio of In contained in the active layer of the second semiconductor laser element, the average wavelength of the first laser light can be made longer than the average wavelength of the second laser light.

[0046] In the present embodiment, one or more first semiconductor laser elements included in the first element group 10 include a plurality of first semiconductor laser elements, and one or more second semiconductor laser elements included in the second element group 20 include a plurality of second semiconductor laser elements. Each of the plurality of first semiconductor laser elements emits laser light of the same wavelength, and each of the plurality of second semiconductor laser elements emits laser light of the same wavelength. In this specification, "the same" means not only the case of being completely the same but also the case of being substantially the same. For example, "the same wavelength" means that the difference in wavelength is about ±1 nm or less. Also, "the same wavelength" may mean that the difference in wavelength is about ±0.5% or less of the wavelength.

[0047] The control circuit 50 is a control unit that controls the power of the laser light emitted by each of the semiconductor laser elements 6. Specifically, the control circuit 50 controls the power of the laser light emitted by each of the semiconductor laser elements 6 by controlling a power supply that supplies current to the semiconductor laser elements 6. The control circuit 50 controls the power of the first laser light emitted by the first element group 10 and the second laser light emitted by the second element group 20, thereby maintaining the combined wavelength, which is the average wavelength of the combined laser light, constant against changes in the power of the combined laser light. In this specification, "constant" means not only a completely constant state, but also a substantially constant state. For example, the average wavelength being "constant" means that the fluctuation of the average wavelength is about ±1 nm or less. In addition, the average wavelength being "constant" may also mean that the fluctuation of the average wavelength is about ±0.5% or less of the average wavelength.

[0048] In this embodiment, the control circuit 50 controls the power ratio between the first laser light and the second laser light by controlling each of the first element group 10 and the second element group 20. This allows the control circuit 50 to control the combined wavelength, which is the average wavelength of the combined laser light. Details of the control method in the control circuit 50 will be described later.

[0049] The combining optical system 60 is an optical system that combines a plurality of laser beams emitted by a plurality of semiconductor laser elements 6. In this embodiment, the combining optical system 60 combines a first laser beam and a second laser beam. The combining optical system 60 emits a combined laser beam including the first laser beam and the second laser beam. The configuration of the combining optical system 60 is not particularly limited. As the combining optical system 60, for example, a focusing element such as a lens may be used, a wavelength dispersion element such as a diffraction grating or a prism may be used, or a polarizing element such as a polarizing plate and a polarizing beam splitter may be used.

[0050] [1-2. Control method] Next, a method for controlling the light source module 1 according to the present embodiment will be described with reference to Figs. 2 to 4D. Fig. 2 is a graph showing the relationship between the power and the average wavelength of the first laser light and the second laser light of the light source module 1 according to the present embodiment. Fig. 2 also shows operating points showing examples of the power of the first laser light and the second laser light included in the combined laser light emitted by the light source module 1. Fig. 3 is a table showing the relationship between the power of the combined laser light, the first laser light, and the second laser light of the light source module 1 according to the present embodiment. Fig. 3 shows the power of each laser light at operating points 1 to 4. Figs. 4A to 4D are graphs showing the light intensity spectrum of the combined laser light at operating points 1 to 4 of the light source module 1 according to the present embodiment, respectively. The horizontal axis of each graph of Figs. 4A to 4D indicates the wavelength, and the vertical axis indicates the light intensity.

[0051] As described above, the control circuit 50 controls the power of each of the first laser light emitted by the first element group 10 and the second laser light emitted by the second element group 20 to maintain the combined wavelength, which is the average wavelength of the combined laser light, constant against changes in the power of the combined laser light. In this embodiment, as shown in FIG. 2, the target average wavelength of the combined laser light is 446.8±1 nm, which is approximately the same as the average wavelength of the first laser light at the minimum power. As shown in FIG. 2, the average wavelength of the first laser light becomes longer as the power increases. Therefore, in order to offset at least a part of the change in the average wavelength of the first laser light, when the average wavelength of the first laser light becomes longer than the target average wavelength, the proportion of the second laser light, which has an average wavelength shorter than that of the first laser light, in the combined laser light is increased. This can reduce the power dependency of the average wavelength of the combined laser light. Note that the average wavelength of the second laser light becomes longer as the power increases.

[0052] In this specification, the average wavelength of a laser beam means a weighted average of the wavelength components contained in the laser beam, weighted by the light intensity. For example, when a laser beam contains a component with a wavelength λx and a light intensity Px, and a component with a wavelength λy and a light intensity Py, the average wavelength λave is expressed by the following formula.

[0053] λave=(Px λx+Py λy) / (Px+Py) For example, at the operating point 1 where the power Pt of the combined laser light is 0.9 W, as shown in FIG. 2 and FIG. 3, the power P1 of the first laser light is 0.9 W, and the power P2 of the second laser light is 0 W. In this case, as shown in FIG. 4A, the combined laser light includes only the first laser light, which is a laser light having an average wavelength near the target average wavelength. In this way, when the power Pt of the combined laser light is small, that is, when the power Pt of the combined laser light is within the range of the power P1 of the first laser light where the average wavelength of the first laser light is about the target average wavelength, the control circuit 50 causes the multiple semiconductor laser elements 6 to emit only the first laser light. In other words, the control circuit 50 controls the multiple semiconductor laser elements 6 so that a current corresponding to the power Pt of the combined laser light is supplied only to the first semiconductor laser element.

[0054] At the operating point 2 where the power Pt of the combined laser light is 4.3 W, as shown in FIG. 2 and FIG. 3, the power P1 of the first laser light is 3.5 W, and the power P2 of the second laser light is 0.8 W. In this case, as shown in FIG. 4B, the combined laser light includes a first laser light having an average wavelength about 3 nm longer than the target average wavelength, and a second laser light having an average wavelength about 11 nm shorter than the target average wavelength and having a significantly smaller power than the first laser light. In this way, when the combined laser light is composed of only the first laser light, if the power Pt of the combined laser light is large enough to make the average wavelength longer than the target average wavelength, the control circuit 50 causes the multiple semiconductor laser elements 6 to emit, in addition to the first laser light, a second laser light having an average wavelength shorter than the first laser light. In other words, the control circuit 50 controls the first semiconductor laser element and the second semiconductor laser element so that a current is supplied to each of them. This makes it possible to make the average wavelength of the combined laser beam shorter than the average wavelength of the first laser beam, thereby setting it to the target average wavelength.

[0055] At the operating point 3 where the power Pt of the combined laser light is 7.5 W, as shown in FIG. 2 and FIG. 3, the power P1 of the first laser light is 5.0 W, and the power P2 of the second laser light is 2.5 W. In this case, as shown in FIG. 4C, the combined laser light includes a first laser light having an average wavelength about 4 nm longer than the target average wavelength, and a second laser light having an average wavelength about 10 nm shorter than the target average wavelength and having a power about half that of the first laser light. Thus, at the operating point 3, as in the operating point 2, the control circuit 50 causes the semiconductor laser elements 6 to emit, in addition to the first laser light, a second laser light having an average wavelength shorter than that of the first laser light. Note that at the operating point 3, the average wavelength of the first laser light is longer than that at the operating point 2, and accordingly, the proportion of the second laser light in the combined laser light is increased.

[0056] At the operating point 4 where the power Pt of the combined laser light is 11.0 W, as shown in FIG. 2 and FIG. 3, the power P1 of the first laser light and the power P2 of the second laser light are both 5.5 W. In this case, as shown in FIG. 4D, the combined laser light includes a first laser light having an average wavelength about 5 nm longer than the target average wavelength, and a second laser light having an average wavelength about 7 nm shorter than the target average wavelength and having a power similar to that of the first laser light. Thus, at the operating point 4, as in the operating points 2 and 3, the control circuit 50 causes the semiconductor laser elements 6 to emit, in addition to the first laser light, a second laser light having an average wavelength shorter than that of the first laser light. At the operating point 4, the average wavelength of the first laser light is longer than that at the operating point 3, and accordingly, the proportion of the second laser light in the combined laser light is further increased. At the operating point 4, all of the semiconductor laser elements included in the plurality of semiconductor laser elements 6 (that is, all of the first semiconductor laser elements and all of the second semiconductor laser elements) are operating at the maximum rated output.

[0057] The above-mentioned operating points are only examples of some of the control modes according to the present embodiment, and even if the power of the combined laser light is different from each of the above-mentioned operating points, the control circuit 50 controls the power of each of the first laser light emitted by the first element group 10 and the second laser light emitted by the second element group 20 to maintain the combined wavelength, which is the average wavelength of the combined laser light, constant with respect to the change in the power Pt of the combined laser light. For example, when the power Pt of the combined laser light is less than 0.9 W, the control circuit 50 causes the semiconductor laser elements 6 to emit only the first laser light, similar to the control mode at the operating point 1. Also, when the power Pt of the combined laser light is greater than 0.9 W and less than 11.0 W, the control circuit 50 causes the semiconductor laser elements 6 to emit the first laser light and the second laser light, similar to the control modes at the operating points 2 to 4.

[0058] As described above, in the light source module 1 according to the present embodiment, the control circuit 50 appropriately controls the power of each of the first laser light and the second laser light, thereby reducing the power dependency of the average wavelength of the combined laser light. Furthermore, the light source module 1 according to the present embodiment does not require a wavelength monitor or the like used in the technology described in Patent Document 1, and therefore has a simplified configuration.

[0059] In this embodiment, the power P1 of the first laser beam is equal to or greater than the power P2 of the second laser beam from when the power Pt of the combined laser beam is at its minimum value to when it is at its maximum value (power Pt is 11.0 W). In this manner, by maintaining the relationship between the power P1 of the first laser beam and the power P2 of the second laser beam, it is possible to maintain the average wavelength of the combined laser beam constant, as described above.

[0060] Furthermore, in this embodiment, if the average wavelength of the first laser light when the power of the combined laser light is a first power is λ11, the average wavelength of the combined laser light is λt1, and the average wavelength of the first laser light when the power of the combined laser light is a second power greater than the first power is λ12, and the average wavelength of the combined laser light is λt2, the following inequality holds.

[0061] λ12-λ11>λt2-λt1 For example, as shown in FIG. 2, when the first power is 4.3 W, which is the power Pt of the combined laser light at the operating point 2, the average wavelength λ11 of the first laser light is about 450 nm, and the average wavelength λt1 of the combined laser light is about 447 nm. On the other hand, when the first power is 7.5 W, which is the power Pt of the combined laser light at the operating point 3, the average wavelength λ12 of the first laser light is about 452 nm, and the average wavelength λt2 of the combined laser light is about 447 nm. Therefore, λ12-λ11 is about 2 nm, and λt2-λt1 is about 0 nm, so the above inequality holds. That is, in the light source module 1, when the power Pt of the combined laser light increases from the first power to the second power, the average wavelength of the first laser light and the average wavelength of the combined laser light may become longer as the power P1 of the first laser light included in the combined laser light increases. In such a case, by combining the combined laser beam with a second laser beam having a shorter average wavelength than the first laser beam, the increase in the wavelength of the combined laser beam can be at least partially offset. In other words, the power dependency of the average wavelength of the combined laser beam can be reduced by using the second laser beam.

[0062] In this embodiment, the control circuit 50 controls the power of the laser light of each of the multiple semiconductor laser elements 6 so that the combined wavelength, which is the average wavelength of the combined laser light, matches the average wavelength of the combined laser light when all of the multiple semiconductor laser elements 6 operate at the maximum rated output. This makes it possible to maintain the average wavelength of the combined laser light constant within a range including the maximum rated power of the combined laser light that can be emitted by the light source module 1 (i.e., the power at the maximum rated output). Therefore, a light source module capable of emitting a high-power combined laser light can be realized.

[0063] In this embodiment, the average wavelength of the combined laser light when all of the semiconductor laser elements 6 operate at the maximum rated output coincides with the average wavelength of the first laser light at the minimum laser output. This makes it possible to maintain the average wavelength constant over the entire range of the combined laser light that can be emitted by the light source module 1, from the minimum power to the maximum rated power.

[0064] In addition, when the power P1 of the first laser light is close to the minimum power, the average wavelength of the first laser light is likely to fluctuate due to temperature changes, etc. When the first laser light and the second laser light are included in the combined laser light with a power close to the minimum power, the power P1 of the first laser light is smaller than when the combined laser light includes only the first laser light, making it difficult to stabilize the average wavelength of the first laser light. In this case, the power P2 of the second laser light is also approximately equal to or less than the power P1 of the first laser light, making it difficult to stabilize the average wavelength of the second laser light. In other words, the average wavelength of the combined laser light can be stabilized by including only the first laser light in the combined laser light with a power close to the minimum power, as in the light source module 1 according to the present embodiment. Maximum rating When the average wavelength of the combined laser beam at the time of output coincides with that of the first laser beam, it is possible to maintain the average wavelength of the combined laser beam at the average wavelength at the minimum power of the first laser beam over the entire range from the minimum power of the combined laser beam to the maximum rated power. In this way, when the average wavelength of the combined laser beam is maintained at the average wavelength at the minimum power of the first laser beam, when the power of the combined laser beam is close to the minimum power, the combined laser beam contains only the first laser beam. Therefore, it is possible to stabilize the average wavelength of the combined laser beam when it is close to the minimum power.

[0065] In this embodiment, the average wavelength of the first laser light at the maximum rated power is 5 nm or more longer than the average wavelength of the first laser light at the minimum power. In this way, even if the average wavelength of the first laser light changes by 5 nm or more depending on the power, the average wavelength of the combined laser light can be kept constant by appropriately controlling the power of the second laser light. Note that the average wavelength of the second laser light at the maximum rated power is 5 nm or more longer than the average wavelength of the second laser light at the minimum power.

[0066] [1-3. Processing method] Next, a processing method using the processing machine 2 according to this embodiment will be described. The processing method according to this embodiment includes a control step of controlling the power of each of the first laser light and the second laser light to maintain the combined wavelength, which is the average wavelength of the combined laser light, constant against changes in the power of the combined laser light. Hereinafter, the control steps included in the processing method according to this embodiment will be described with reference to FIG. 5. FIG. 5 is a flowchart showing control step S1 included in the processing method using the processing machine 2 according to this embodiment. As shown in FIG. 5, control step S1 includes steps S10 to S18.

[0067] 5, in control step S1, first, the power Pt of the combined laser beam emitted from the processing machine 2 is set (S10). The power Pt of the combined laser beam is set based on the material to be processed, etc. The power Pt of the combined laser beam may be automatically set in the control circuit 50, or may be set based on a signal input from the outside by a user, etc.

[0068] Next, the control circuit 50 controls the power of each laser light based on the power set in step S10 (S12). Specifically, the control circuit 50 determines the power of each of the first laser light and the second laser light based on the power relationship between the combined laser light and the first and second laser lights as shown in Fig. 2 and Fig. 3. Next, the control circuit 50 controls the current supplied to each of the first and second semiconductor laser elements based on the respective powers. As a result, the power of the combined laser light becomes the power set in step S10.

[0069] Next, the processing machine 2 irradiates the combined laser light onto the material to be processed (S14).

[0070] Next, the control circuit 50 judges whether or not to continue irradiating the material with the combined laser light (S16). For example, the control circuit 50 may determine an irradiation time using a timer or the like, continue irradiation until the set irradiation time has elapsed, and stop irradiation when the irradiation time has elapsed. Alternatively, the control circuit 50 may continue irradiation until a signal instructing to stop irradiation is input from the outside, and stop irradiation when the signal is input.

[0071] If the control circuit 50 does not continue the irradiation of the combined laser beam (No in S16), the control circuit 50 ends the processing. On the other hand, if the control circuit 50 continues the irradiation of the combined laser beam (Yes in S16), the control circuit 50 determines whether or not to change the power of the combined laser beam (S18). For example, the control circuit 50 may determine whether or not to change the power based on the presence or absence of a signal indicating a power change input from the outside, or may determine whether or not to change the power based on a predetermined relationship between the irradiation time and the power.

[0072] If the control circuit 50 changes the power of the combined laser beam (Yes in S18), the process returns to step S10 and sets the power of the combined laser beam. At this time, even if the power of the combined laser beam is changed, the average wavelength of the combined laser beam is maintained constant. On the other hand, if the control circuit 50 does not change the power of the combined laser beam (No in S18), the control circuit 50 returns to step S14 and continues irradiating the combined laser beam.

[0073] As described above, in the control step of the processing method according to the present embodiment, the material can be irradiated with the combined laser beam while changing the power of the combined laser beam. In this way, even if processing is performed while varying the power of the combined laser beam, the fluctuation of the average wavelength of the combined laser beam is reduced, so stable processing is possible.

[0074] In the processing method according to the present embodiment, the material to be processed is not particularly limited, but the material may include Au or Cu. Au and Cu have a relatively large wavelength dependency of absorptance, but when processing such a material, the processing method according to the present embodiment reduces the power dependency of the average wavelength, so that stable processing is possible even when the power is changed. In addition, Au or Cu has a relatively high absorptance to blue laser light, so that materials containing Au or Cu can be efficiently processed by using semiconductor laser elements containing nitride semiconductors as the multiple semiconductor laser elements 6.

[0075] In the processing method according to the present embodiment, the average wavelength of the combined laser light is kept constant, but the appropriateness of using the average wavelength of the combined laser light in evaluating the absorptance and absorption coefficient of the combined laser light in the material will be described with reference to Figures 6A and 6B. Figures 6A and 6B are schematic graphs showing the relationship between the intensity distribution of the combined laser light and the absorption coefficient of the material to be processed when the range of wavelengths included in the combined laser light is narrow and wide, respectively. In Figures 6A and 6B, the horizontal axis indicates the wavelength, the vertical axis on the left indicates the absorption coefficient of the material to be processed (the material to be processed), and the vertical axis on the right indicates the laser light intensity. The absorption coefficients in Figures 6A and 6B are absorption coefficients for the same material to be processed, and in this material to be processed, the absorption coefficient decreases as the wavelength becomes longer.

[0076] As shown in FIG. 6A and FIG. 6B, the absorption coefficient of the material to be processed generally changes nonlinearly with respect to wavelength, so that when the combined laser light contains multiple wavelengths, the actual absorption coefficient of the combined laser light does not necessarily match the absorption coefficient at the average wavelength of the combined laser light. In particular, as shown in FIG. 6B, when the range of wavelengths contained in the combined laser light is wide, the difference between the actual absorption coefficient of the combined laser light and the absorption coefficient at the average wavelength of the combined laser light is large. However, as shown in FIG. 6A, when the range of wavelengths contained in the combined laser light is narrow, the absorption coefficient of the material to be processed can be considered to be approximately linear with respect to wavelength within the wavelength range. Therefore, the difference between the actual absorption coefficient of the combined laser light and the absorption coefficient at the average wavelength of the combined laser light can be sufficiently small to be negligible. For example, if the range of wavelengths contained in the combined laser light is about 20 nm or less, in many materials, the difference between the actual absorption coefficient of the combined laser light and the absorption coefficient at the average wavelength of the combined laser light is sufficiently small to be negligible. Therefore, the difference in average wavelength between the first laser light and the second laser light may be 20 nm or less.

[0077] (Embodiment 2) A light source module according to embodiment 2 will be described. The light source module according to this embodiment differs from light source module 1 according to embodiment 1 mainly in that the plurality of semiconductor laser elements includes three element groups. The light source module according to this embodiment will be described below, focusing on the differences from light source module 1 according to embodiment 1.

[0078] [2-1. Overall composition] First, the overall configuration of the light source module according to the present embodiment will be described with reference to Fig. 7. Fig. 7 is a block diagram showing the functional configuration of a light source module 101 according to the present embodiment. As shown in Fig. 7, the light source module 101 according to the present embodiment includes a plurality of semiconductor laser elements 106, a control circuit 150, and a beam-combining optical system 160.

[0079] The multiple semiconductor laser elements 106 include a first element group 110 including one or more first semiconductor laser elements and emitting a first laser light, a second element group 120 including one or more second semiconductor laser elements and emitting a second laser light, and a third element group 130 including one or more third semiconductor laser elements and emitting a third laser light. The first semiconductor laser element included in the first element group 110, the second semiconductor laser element included in the second element group 120, and the third semiconductor laser element included in the third element group 130 emit laser light with different wavelengths. When the power of the first laser light, the power of the second laser light, and the power of the third laser light are equal, the average wavelength of the first laser light is longer than the average wavelength of the second laser light, and the average wavelength of the second laser light is longer than the average wavelength of the third laser light. Moreover, the average wavelength of the first laser beam is equal to or greater than the average wavelength of the combined laser beam, and the average wavelength of the third laser beam is equal to or less than the average wavelength of the combined laser beam.

[0080] In the present embodiment, the one or more first semiconductor laser elements included in the first element group 110 include a plurality of first semiconductor laser elements, the one or more second semiconductor laser elements included in the second element group 120 include a plurality of second semiconductor laser elements, and the one or more third semiconductor laser elements included in the third element group 130 include a plurality of third semiconductor laser elements. Each of the plurality of first semiconductor laser elements emits laser light of the same wavelength, each of the plurality of second semiconductor laser elements emits laser light of the same wavelength, and each of the plurality of third semiconductor laser elements emits laser light of the same wavelength.

[0081] The control circuit 150 is a control unit that controls the power of the laser light emitted from each of the multiple semiconductor laser elements 106. The control circuit 150 controls the power of each of the first laser light emitted by the first element group 110, the second laser light emitted by the second element group 120, and the third laser light emitted by the third element group 130, thereby maintaining the combined wavelength, which is the average wavelength of the combined laser light, constant against changes in the power of the combined laser light.

[0082] In this embodiment, the control circuit 150 controls the power ratio between the first laser light, the second laser light, and the third laser light by controlling each of the first element group 110, the second element group 120, and the third element group 130. This allows the control circuit 150 to control the combined wavelength, which is the average wavelength of the combined laser light. Details of the control method in the control circuit 150 will be described later.

[0083] The beam combining optical system 160 is an optical system that combines a plurality of laser beams emitted by a plurality of semiconductor laser elements 106. In this embodiment, the beam combining optical system 160 combines a first laser beam, a second laser beam, and a third laser beam. The beam combining optical system 160 emits a combined laser beam including the first laser beam, the second laser beam, and the third laser beam.

[0084] [2-2. Control method] Next, a method for controlling the light source module 101 according to the present embodiment will be described with reference to Figs. 8 to 10E. Fig. 8 is a graph showing the relationship between the power and the average wavelength of the first laser light, the second laser light, and the third laser light of the light source module 101 according to the present embodiment. Fig. 8 also shows operating points 1 to 6 showing examples of the power of the first laser light, the second laser light, and the third laser light included in the combined laser light emitted by the light source module 101. Fig. 9 is a table showing the relationship between the power of the combined laser light, the first laser light, the second laser light, and the third laser light of the light source module 101 according to the present embodiment. Fig. 9 shows the power of each laser light at operating points 1 to 5. Figs. 10A to 10E are graphs showing the light intensity spectrum of the combined laser light at operating points 1 to 5 of the light source module 101 according to the present embodiment, respectively. The horizontal axis of each graph of Figs. 10A to 10E indicates the wavelength, and the vertical axis indicates the light intensity.

[0085] As described above, the control circuit 150 controls the power of each of the first laser light emitted by the first element group 110, the second element group 120, and the third laser light emitted by the third element group 130, thereby maintaining the combined wavelength, which is the average wavelength of the combined laser light, constant against changes in the power of the combined laser light. In this embodiment, as shown in FIG. 8, the target average wavelength of the combined laser light is 446.6±1 nm, which is approximately the same as the average wavelength of the first laser light at the minimum power. As shown in FIG. 8, the average wavelengths of the first, second, and third laser lights become longer as the power increases. Therefore, in order to offset at least a part of the change in the average wavelength of the first laser light, when the average wavelength of the first laser light becomes longer than the target average wavelength, the proportion of at least one of the second laser light and the third laser light, which has an average wavelength shorter than that of the first laser light, in the combined laser light is increased. This can reduce the power dependency of the average wavelength of the combined laser light.

[0086] For example, at the operating point 1 where the power Pt of the combined laser light is 0.9 W, as shown in FIG. 8 and FIG. 9, the power P1 of the first laser light is 0.9 W, and the power P2 of the second laser light and the power P3 of the third laser light are 0 W. In this case, as shown in FIG. 10A, the combined laser light includes only the first laser light, which is a laser light having an average wavelength near the target average wavelength. In this way, when the power Pt of the combined laser light is small, that is, when the power Pt of the combined laser light is within the range of the power P1 of the first laser light where the average wavelength of the first laser light is about the target average wavelength, the control circuit 150 causes the multiple semiconductor laser elements 106 to emit only the first laser light. In other words, the control circuit 150 controls so that a current corresponding to the power Pt of the combined laser light is supplied only to the first semiconductor laser element among the multiple semiconductor laser elements 106.

[0087] At the operating point 2 where the power Pt of the combined laser light is 3.1 W, as shown in Fig. 8 and Fig. 9, the power P1 of the first laser light is 2.3 W, the power P2 of the second laser light is 0.8 W, and the power P3 of the third laser light is 0 W. In this case, as shown in Fig. 10B, the combined laser light includes a first laser light having an average wavelength about 1 nm longer than the target average wavelength, and a second laser light having an average wavelength about 6 nm shorter than the target average wavelength and having a significantly smaller power than the first laser light. In this way, if the combined laser light is composed of only the first laser light, when the power Pt of the combined laser light is large enough to make the average wavelength longer than the target average wavelength, the control circuit 150 causes the multiple semiconductor laser elements 6 to emit at least one of the second laser light and the third laser light, which have an average wavelength shorter than that of the first laser light, in addition to the first laser light. In the example of the operating point 2, the control circuit 150 emits only the second laser light out of the second laser light and the third laser light. That is, the control circuit 150 controls so that a current is supplied to each of the first semiconductor laser element and the second semiconductor laser element. This makes it possible to make the average wavelength of the combined laser light shorter than the average wavelength of the first laser light, and set it to the target average wavelength.

[0088] At the operating point 3 where the power Pt of the combined laser light is 6.0 W, as shown in Fig. 8 and Fig. 9, the power P1 of the first laser light is 3.5 W, the power P2 of the second laser light is 2.5 W, and the power P3 of the third laser light is 0 W. In this case, as shown in Fig. 10C, the combined laser light includes a first laser light having an average wavelength about 2 nm longer than the target average wavelength, and a second laser light having an average wavelength about 5 nm shorter than the target average wavelength and having a power of about 70% of the power of the first laser light. Thus, at the operating point 3, as in the operating point 2, the control circuit 150 causes the semiconductor laser elements 106 to emit, in addition to the first laser light, the second laser light having an average wavelength shorter than that of the first laser light.

[0089] At the operating point 4 where the power Pt of the combined laser light is 11.5 W, as shown in Fig. 8 and Fig. 9, the power P1 of the first laser light is 5.0 W, the power P2 of the second laser light is 4.5 W, and the power P3 of the third laser light is 2.0 W. In this case, as shown in Fig. 10D, the combined laser light includes a first laser light having an average wavelength about 4 nm longer than the target average wavelength, a second laser light having an average wavelength about 2 nm shorter than the target average wavelength and having a power of about 90% of the power of the first laser light, and a third laser light having an average wavelength about 11 nm shorter than the target average wavelength and having a power of about 40% of the power of the first laser light. Thus, at the operating point 4, the control circuit 150 causes the multiple semiconductor laser elements 106 to emit, in addition to the first laser light, the second laser light and the third laser light having an average wavelength shorter than the first laser light. In this way, by emitting the third laser beam in addition to the first and second laser beams, the power of the combined laser beam can be increased to be greater than the maximum value of the power of the combined laser beam according to embodiment 1. Moreover, the average wavelength of the combined laser beam is maintained constant.

[0090] At the operating point 5 where the power Pt of the combined laser light is 16.5 W, as shown in FIG. 8 and FIG. 9, the power P1 of the first laser light, the power P2 of the second laser light, and the power P3 of the third laser light are all 5.5 W. In this case, as shown in FIG. 10E, the combined laser light includes the first laser light having an average wavelength about 5 nm longer than the target average wavelength, the second laser light having an average wavelength about 1 nm shorter than the target average wavelength, and the third laser light having an average wavelength about 5 nm shorter than the target average wavelength. Thus, at the operating point 4, the control circuit 150 causes the multiple semiconductor laser elements 106 to emit the first laser light, the second laser light, and the third laser light. In this way, by emitting the first laser light, the second laser light, and the third laser light, the power of the combined laser light can be significantly increased from the maximum value of the power of the combined laser light according to the first embodiment. Moreover, the average wavelength of the combined laser light is maintained constant.

[0091] Note that the above operating points are only examples of some of the control modes according to this embodiment, and even if the power of the combined laser light is different from each of the above operating points, the control circuit 150 controls the power of each of the first laser light emitted by the first element group 110, the second laser light emitted by the second element group 120, and the third laser light emitted by the third element group 130, thereby maintaining the combined wavelength, which is the average wavelength of the combined laser light, constant against changes in the power Pt of the combined laser light.

[0092] In addition, at each operating point of the light source module 101 described above, the power of the first laser light, the second laser light, and the third laser light are smaller in this order, but the magnitude relationship of the power of each laser light is not limited to this. For example, as in the operating point 6 shown in FIG. 8, the power P2 of the second laser light may be the largest. When the combined laser light includes three or more laser lights as in the light source module 101 according to the present embodiment, the power of one of the three or more laser lights is equal to or greater than the power of at least one laser light having a shorter wavelength than the laser light. In addition, when the combined laser light includes three or more laser lights, the combination of each power of the three or more laser lights to obtain the power Pt and average wavelength of the combined laser light equivalent to each operating point is not necessarily limited to one.

[0093] As described above, even in light source module 101 in which multiple semiconductor laser elements 106 include three element groups, the power dependency of the average wavelength of the combined laser light can be reduced, similarly to light source module 1 according to embodiment 1. Furthermore, light source module 101 according to this embodiment does not require a wavelength monitor or the like used in the technology described in Patent Document 1, and therefore has a simplified configuration.

[0094] (Embodiment 3) A light source module according to a third embodiment will be described. The light source module according to this embodiment differs from the light source module 101 according to the second embodiment in that each element group includes one semiconductor laser element. In addition, in the light source module according to this embodiment, a specific example of an optical system such as a multiplexing optical system is shown. The light source module according to this embodiment will be described below with reference to FIG. 11, focusing on the differences from the light source module 101 according to the second embodiment.

[0095] FIG. 11 is a perspective view showing a configuration of a light source module 201 according to the present embodiment. FIG. 11 also shows a light guide unit 270. In the present embodiment, the light guide unit 270 is an optical fiber that guides the combined laser light. The light source module 201 according to the present embodiment includes a plurality of semiconductor laser elements and a control circuit, similar to the light source module 101 according to the second embodiment. Note that the control circuit is not shown in FIG. 11. The light source module 201 according to the present embodiment further includes a base 208, power sources 214, 224, and 234, submounts 213, 223, and 233, fast axis collimators 216, 226, and 236, slow axis collimators 218, 228, and 238, and a combined optical system 260.

[0096] The semiconductor laser elements include a first element group including a first semiconductor laser element 212 and emitting a first laser beam, a second element group including a second semiconductor laser element 222 and emitting a second laser beam, and a third element group including a third semiconductor laser element 232 and emitting a third laser beam. The first semiconductor laser element 212, the second semiconductor laser element 222, and the third semiconductor laser element 232 emit laser beams having different wavelengths. When the powers of the first laser beam, the second laser beam, and the third laser beam are equal, the average wavelength of the first laser beam is longer than the average wavelength of the second laser beam, and the average wavelength of the second laser beam is longer than the average wavelength of the third laser beam. In addition, the average wavelength of the first laser beam is equal to or longer than the average wavelength of the combined laser beam, and the average wavelength of the third laser beam is equal to or shorter than the average wavelength of the combined laser beam.

[0097] The base 208 is a member on which a plurality of semiconductor laser elements are arranged. In this embodiment, a part of the beam-combining optical system 260 and other optical elements are also arranged on the base 208. The base 208 has a stepped shape and has three mounting surfaces with different heights. As shown in FIG. 11, a semiconductor laser element and the like are arranged on each mounting surface of the base 208. In this embodiment, as shown in FIG. 11, the first semiconductor laser element 212, the submount 213, the fast axis collimator 216, the slow axis collimator 218, and the reflecting mirror 261 are arranged on the highest mounting surface of the base 208. The second semiconductor laser element 222, the submount 223, the fast axis collimator 226, the slow axis collimator 228, and the reflecting mirror 262 are arranged on the second highest mounting surface of the base 208. The third semiconductor laser element 232, the submount 233, the fast axis collimator 236, the slow axis collimator 238, and the reflecting mirror 263 are arranged on the lowest mounting surface of the base 208. The first semiconductor laser element 212, the second semiconductor laser element 222, and the third semiconductor laser element 232 are arranged one-dimensionally at equal intervals. In other words, the first semiconductor laser element 212, the second semiconductor laser element 222, and the third semiconductor laser element 232 are arranged in a row at equal intervals. Note that a deflecting element such as a prism may be used instead of the reflecting mirror.

[0098] The power supplies 214, 224, and 234 are devices that supply current to the first semiconductor laser element 212, the second semiconductor laser element 222, and the third semiconductor laser element 232, respectively. Each power supply is controlled by a control circuit (not shown). This controls the current supplied to each semiconductor laser element.

[0099] The submounts 213, 223, and 233 are bases on which the first semiconductor laser element 212, the second semiconductor laser element 222, and the third semiconductor laser element 232 are respectively arranged, and are members having a rectangular parallelepiped shape in this embodiment. A conductive layer is formed on the surface of each submount on which the semiconductor laser element is arranged, the semiconductor laser element is mounted on the layer, and a current is supplied to the semiconductor laser element via the layer.

[0100] Fast axis collimators 216, 226, and 236 are optical elements that collimate the laser light emitted from first semiconductor laser element 212, second semiconductor laser element 222, and third semiconductor laser element 232, respectively, in the fast axis direction. Each fast axis collimator is disposed near the laser light emission surface of each semiconductor laser element. For example, an aspherical lens such as a cylindrical lens can be used as each fast axis collimator. Note that an aspherical mirror such as a cylindrical mirror may also be used as each fast axis collimator.

[0101] The slow axis collimators 218, 228, and 238 are optical elements that collimate the laser light emitted from the first semiconductor laser element 212, the second semiconductor laser element 222, and the third semiconductor laser element 232, respectively, in the slow axis direction. Each slow axis collimator is disposed downstream of each laser light from each fast axis collimator. For example, an aspherical lens such as a cylindrical lens can be used as each slow axis collimator. Note that an aspherical mirror such as a cylindrical mirror may also be used as each slow axis collimator.

[0102] The combining optical system 260 is an optical system that combines a plurality of laser beams emitted by a plurality of semiconductor laser elements. In this embodiment, the combining optical system 260 combines a first laser beam, a second laser beam, and a third laser beam. The combining optical system 260 emits a combined laser beam including the first laser beam, the second laser beam, and the third laser beam. The combining optical system 260 has reflection mirrors 261, 262, and 263, and a focusing element 268.

[0103] Reflecting mirrors 261, 262, and 263 are optical elements that reflect the first laser light, the second laser light, and the third laser light, respectively. Each reflecting mirror reflects the propagation direction of the incident laser light toward the light collecting element 268. For example, a flat mirror or the like can be used as each reflecting mirror.

[0104] The light collecting element 268 is an optical element that collects and combines a plurality of incident laser beams. In this embodiment, the light collecting element 268 collects the first laser beam, the second laser beam, and the third laser beam to form a combined laser beam. In the example shown in FIG. 11, the combined laser beam emitted from the light collecting element 268 is incident on the light guiding section 270. For example, a lens such as a spherical lens can be used as the light collecting element 268. Note that a collecting mirror such as a spherical mirror may also be used as the light collecting element 268.

[0105] The light source module 201 according to this embodiment also provides the same effects as the light source modules according to the above-described embodiments.

[0106] (Embodiment 4) A light source module according to the fourth embodiment will be described. The light source module according to this embodiment differs from the light source module 201 according to the third embodiment in that each element group includes two semiconductor laser elements. The light source module according to this embodiment also differs from the light source module 201 according to the third embodiment in that the two semiconductor laser elements included in each element group are connected in series. The light source module according to this embodiment will be described below with reference to FIG. 12, focusing on the differences from the light source module 101 according to the second embodiment.

[0107] FIG. 12 is a perspective view showing a configuration of a light source module 301 according to the present embodiment. FIG. 12 also shows a light guide section 270 that functions as a light guide section. The light source module 301 according to the present embodiment includes a plurality of semiconductor laser elements and a control circuit, similar to the light source module 201 according to the third embodiment. Note that the control circuit is not shown in FIG. 12. The light source module 301 according to the present embodiment further includes a base 308, power sources 314, 324, and 334, submounts 313a, 313b, 323a, 323b, 333a, and 333b, fast axis collimators 316a, 316b, 326a, 326b, 336a, and 336b, slow axis collimators 318a, 318b, 328a, 328b, 338a, and 338b, and a beam-combining optical system 360.

[0108] The semiconductor laser elements include a first element group including first semiconductor laser elements 312a and 312b and emitting a first laser light, a second element group including second semiconductor laser elements 322a and 322b and emitting a second laser light, and a third element group including third semiconductor laser elements 332a and 332b and emitting a third laser light. The first semiconductor laser elements 312a and 312b, the second semiconductor laser elements 322a and 322b, and the third semiconductor laser elements 332a and 332b emit laser lights with different wavelengths. When the powers of the first laser light, the second laser light, and the third laser light are equal, the average wavelength of the first laser light is longer than the average wavelength of the second laser light, and the average wavelength of the second laser light is longer than the average wavelength of the third laser light. Moreover, the average wavelength of the first laser beam is equal to or greater than the average wavelength of the combined laser beam, and the average wavelength of the third laser beam is equal to or less than the average wavelength of the combined laser beam.

[0109] Base 308 is a member on which a plurality of semiconductor laser elements are arranged. In this embodiment, a part of beam-combining optical system 360 and other optical elements are also arranged on base 308. Base 308 has a stepped shape and six mounting surfaces with different heights. As shown in Fig. 12, a semiconductor laser element and the like are arranged on each mounting surface of base 308.

[0110] The power supplies 314, 324, and 334 are devices that supply current to the first semiconductor laser elements 312a and 312b, the second semiconductor laser elements 322a and 322b, and the third semiconductor laser elements 332a and 332b, respectively. Each power supply is controlled by a control circuit (not shown). This controls the current supplied to each semiconductor laser element. In this embodiment, the first semiconductor laser elements 312a and 312b are connected in series. The second semiconductor laser elements 322a and 322b are also connected in series, and the third semiconductor laser elements 332a and 332b are also connected in series.

[0111] In this embodiment, the first semiconductor laser elements 312a and 312b, the second semiconductor laser elements 322a and 322b, and the third semiconductor laser elements 332a and 332b are arranged adjacent to each other and connected in series, but they do not necessarily have to be adjacent to each other. For example, the first semiconductor laser elements 312a and 312b may be arranged at the top and bottom of a six-step step-like mounting surface, as long as they are electrically connected in series. Alternatively, the first semiconductor laser elements 312a and 312b, the second semiconductor laser elements 322a and 322b, and the third semiconductor laser elements 332a and 332b may be arranged adjacent to each other on the same mounting surface and connected in series.

[0112] The submounts 313a and 313b are bases on which the first semiconductor laser elements 312a and 312b are disposed, respectively. The submounts 323a and 323b are bases on which the second semiconductor laser elements 322a and 322b are disposed, respectively. The submounts 333a and 333b are bases on which the third semiconductor laser elements 332a and 332b are disposed, respectively. Each submount according to the present embodiment has the same configuration as each submount according to the third embodiment.

[0113] The fast-axis collimators 316a and 316b are optical elements that collimate the laser beams emitted from the first semiconductor laser elements 312a and 312b, respectively, in the fast-axis direction. The fast-axis collimators 326a and 326b are optical elements that collimate the laser beams emitted from the second semiconductor laser elements 322a and 322b, respectively, in the fast-axis direction. The fast-axis collimators 336a and 336b are optical elements that collimate the laser beams emitted from the third semiconductor laser elements 332a and 332b, respectively, in the fast-axis direction. Each fast-axis collimator according to this embodiment has the same configuration as each fast-axis collimator according to the third embodiment.

[0114] The slow axis collimators 318a and 318b are optical elements that collimate the laser beams emitted from the first semiconductor laser elements 312a and 312b in the slow axis direction, respectively. The slow axis collimators 328a and 328b are optical elements that collimate the laser beams emitted from the second semiconductor laser elements 322a and 322b in the slow axis direction, respectively. The slow axis collimators 338a and 338b are optical elements that collimate the laser beams emitted from the third semiconductor laser elements 332a and 332b in the slow axis direction, respectively. Each slow axis collimator according to this embodiment has the same configuration as each slow axis collimator according to the third embodiment.

[0115] The combining optical system 360 is an optical system that combines a plurality of laser beams emitted by a plurality of semiconductor laser elements. In this embodiment, the combining optical system 360 combines a first laser beam, a second laser beam, and a third laser beam. The first laser beam includes laser beams emitted by the first semiconductor laser elements 312a and 312b. The second laser beam includes laser beams emitted by the second semiconductor laser elements 322a and 322b. The third laser beam includes laser beams emitted by the third semiconductor laser elements 332a and 332b. The combining optical system 360 emits a combined laser beam including the first laser beam, the second laser beam, and the third laser beam. The combining optical system 360 has reflecting mirrors 361a, 361b, 362a, 362b, 363a, and 363b, and a focusing element 368.

[0116] The reflecting mirrors 361a and 361b are optical elements that reflect the laser beams emitted by the first semiconductor laser elements 312a and 312b, respectively, of the first laser beam. The reflecting mirrors 362a and 362b are optical elements that reflect the laser beams emitted by the second semiconductor laser elements 322a and 322b, respectively, of the second laser beam. The reflecting mirrors 363a and 363b are optical elements that reflect the laser beams emitted by the third semiconductor laser elements 332a and 332b, respectively, of the third laser beam. Each reflecting mirror according to this embodiment has the same configuration as each reflecting mirror according to the third embodiment.

[0117] The light-collecting element 368 is an optical element that combines a plurality of incident laser beams by collecting them. In this embodiment, the light-collecting element 368 collects the first laser beam, the second laser beam, and the third laser beam to form a combined laser beam. The light-collecting element 368 has a similar configuration to the light-collecting element 268 according to the third embodiment.

[0118] The light source module 301 according to this embodiment also provides the same effects as the light source modules according to the above embodiments. Moreover, in this embodiment, by connecting a plurality of semiconductor laser elements in series in each element group, the amount of current required to drive the light source module 301 can be reduced compared to the case of connecting them in parallel. Therefore, the power supplies 314, 324, and 334 required to drive the light source module 301 can be made smaller.

[0119] (Variations, etc.) Although the light source module, processing machine, and processing method according to the present disclosure have been described based on the respective embodiments, the present disclosure is not limited to the above-described respective embodiments.

[0120] For example, in the processing machine 2 according to the above-mentioned first embodiment, the light source module 1 may be replaced with any of the light source modules according to the second to fourth embodiments.

[0121] Furthermore, in the above first, second and fourth embodiments, each element group includes a plurality of semiconductor laser elements, but each element group may include only a single semiconductor laser element.

[0122] In addition, in each of the above embodiments, the average wavelength of the combined laser light when all of the multiple semiconductor laser elements operate at their maximum rated output matches the average wavelength of the first laser light at the minimum laser output, but this does not necessarily have to be the case.

[0123] In addition, in each of the above-described embodiments, a semiconductor laser element including a nitride-based semiconductor is used as the semiconductor laser element included in the plurality of semiconductor laser elements. However, a semiconductor laser element of another material system, such as a GaAs-based semiconductor laser element, may be used as the semiconductor laser element included in the plurality of semiconductor laser elements.

[0124] Furthermore, in each of the above embodiments, the plurality of semiconductor laser elements includes two or three element groups, but may include four or more element groups.

[0125] Furthermore, in the above-mentioned first embodiment, an example has been shown in which the light source module 1 is included in the processing machine 2, but the light source module 1 may be used in equipment other than the processing machine 2, such as a lighting device.

[0126] In the third and fourth embodiments, the semiconductor laser elements are arranged one-dimensionally, but may be arranged two-dimensionally. For example, a stack structure in which semiconductor laser elements are arranged on top of each other may be adopted as the arrangement structure of the semiconductor laser elements.

[0127] In addition, the present disclosure also includes forms obtained by applying various modifications to the above-described embodiments that a person skilled in the art may conceive, and forms realized by arbitrarily combining the components and functions of the above-described embodiments within the scope that does not deviate from the spirit of the present disclosure. [Industrial Applicability]

[0128] The light source module of the present disclosure can be applied, for example, to a laser processing machine capable of high output and stable processing. [Explanation of symbols]

[0129] 1, 101, 201, 301 Light source module 2 Processing machine 6, 106 multiple semiconductor laser elements 10, 110 First element group 20, 120 Second element group 50, 150 Control circuit 60, 160, 260, 360 multiplexing optical system 70, 270 Light guide section 130 Third Element Group 208, 308 base 212, 312a, 312b First semiconductor laser element 213, 223, 233, 313a, 313b, 323a, 323b, 333a, 333b submounts 214, 224, 234, 314, 324, 334 power supply 216, 226, 236, 316a, 316b, 326a, 326b, 336a, 336b Fast Axis Collimators 218, 228, 238, 318a, 318b, 328a, 328b, 338a, 338b Slow axis collimators 222, 322a, 322b Second semiconductor laser element 232, 332a, 332b Third semiconductor laser element 261, 262, 263, 361a, 361b, 362a, 362b, 363a, 363b Reflecting mirror 268, 368 Condenser element

Claims

1. A light source module that emits a combined laser beam, A plurality of semiconductor laser elements; a control circuit for controlling the power of laser light emitted by each of the plurality of semiconductor laser elements; The plurality of semiconductor laser elements include a first element group including one or more first semiconductor laser elements and emitting a first laser beam; a second element group including one or more second semiconductor laser elements and emitting a second laser beam; the combined laser beam includes at least one of the first laser beam and the second laser beam, the control circuit controls the power of each of the first laser light and the second laser light to maintain a combined wavelength, which is an average wavelength of the combined laser light, constant against changes in the power of the combined laser light; when a power of the first laser light and a power of the second laser light are equal, an average wavelength of the first laser light is longer than an average wavelength of the second laser light, an average wavelength of the first laser light increases as the power of the first laser light increases; and The control circuit controls the power of each of the first laser light and the second laser light such that a ratio of the second laser light in the combined laser light increases as the power of the first laser light increases. Light source module.

2. When the power of the combined laser beam is a first power, the average wavelength of the first laser beam is λ11 and the combined wavelength is λt1; When the power of the combined laser light is a second power greater than the first power, the average wavelength of the first laser light is λ12 and the combined wavelength is λt2, λ12-λ11>λt2-λt1 holds The light source module according to claim 1 .

3. A light source module that emits a combined laser beam, A plurality of semiconductor laser elements; a control circuit for controlling the power of laser light emitted by each of the plurality of semiconductor laser elements; The plurality of semiconductor laser elements include a first element group including one or more first semiconductor laser elements and emitting a first laser beam; a second element group including one or more second semiconductor laser elements and emitting a second laser beam; the combined laser beam includes at least one of the first laser beam and the second laser beam, the control circuit controls the power of each of the first laser light and the second laser light to maintain a combined wavelength, which is an average wavelength of the combined laser light, constant against changes in the power of the combined laser light; when a power of the first laser light and a power of the second laser light are equal, an average wavelength of the first laser light is longer than an average wavelength of the second laser light, When the power of the combined laser beam is a first power, the average wavelength of the first laser beam is λ11 and the combined wavelength is λt1; When the power of the combined laser light is a second power greater than the first power, the average wavelength of the first laser light is λ12 and the combined wavelength is λt2, λ12-λ11>λt2-λt1 holds Light source module.

4. The average wavelength of the combined laser light when all of the plurality of semiconductor laser elements are operated at the maximum rated output coincides with the average wavelength of the first laser light at the minimum laser output. The light source module according to any one of claims 1 to 3.

5. A light source module that emits a combined laser beam, A plurality of semiconductor laser elements; a control circuit for controlling the power of laser light emitted by each of the plurality of semiconductor laser elements; The plurality of semiconductor laser elements include a first element group including one or more first semiconductor laser elements and emitting a first laser beam; a second element group including one or more second semiconductor laser elements and emitting a second laser beam; the combined laser beam includes at least one of the first laser beam and the second laser beam, the control circuit controls the power of each of the first laser light and the second laser light to maintain a combined wavelength, which is an average wavelength of the combined laser light, constant against changes in the power of the combined laser light; when a power of the first laser light and a power of the second laser light are equal, an average wavelength of the first laser light is longer than an average wavelength of the second laser light, The average wavelength of the combined laser light when all of the plurality of semiconductor laser elements are operated at the maximum rated output coincides with the average wavelength of the first laser light at the minimum laser output. Light source module.

6. The control circuit controls the power of the laser light of each of the plurality of semiconductor laser elements so that the combined wavelength coincides with an average wavelength of the combined laser light when all of the plurality of semiconductor laser elements operate at maximum rated output. The light source module according to any one of claims 1 to 5.

7. A light source module that emits a combined laser beam, A plurality of semiconductor laser elements; a control circuit for controlling the power of laser light emitted by each of the plurality of semiconductor laser elements; The plurality of semiconductor laser elements include a first element group including one or more first semiconductor laser elements and emitting a first laser beam; a second element group including one or more second semiconductor laser elements and emitting a second laser beam; the combined laser beam includes at least one of the first laser beam and the second laser beam, the control circuit controls the power of each of the first laser light and the second laser light to maintain a combined wavelength, which is an average wavelength of the combined laser light, constant against changes in the power of the combined laser light; when a power of the first laser light and a power of the second laser light are equal, an average wavelength of the first laser light is longer than an average wavelength of the second laser light, The control circuit controls the power of the laser light of each of the plurality of semiconductor laser elements so that the combined wavelength coincides with an average wavelength of the combined laser light when all of the plurality of semiconductor laser elements operate at maximum rated output. Light source module.

8. The power of the first laser light is equal to or greater than the power of the second laser light. The light source module according to any one of claims 1 to 7.

9. the one or more first semiconductor laser elements include a plurality of first semiconductor laser elements, Each of the plurality of first semiconductor laser elements emits laser light of the same wavelength. The light source module according to any one of claims 1 to 8.

10. The plurality of first semiconductor laser elements are connected in series. The light source module according to claim 9 .

11. The average wavelength of the first laser beam at a maximum rated power is longer than the average wavelength at a minimum power by 5 nm or more. The light source module according to any one of claims 1 to 10.

12. The one or more first semiconductor laser elements and the one or more second semiconductor laser elements each include a nitride-based semiconductor. The light source module according to any one of claims 1 to 11.

13. The difference between the average wavelength of the first laser beam and the average wavelength of the second laser beam is 20 nm or less. The light source module according to any one of claims 1 to 12.

14. The multiplexed wavelength is 400 nm or more and 500 nm or less. The light source module according to any one of claims 1 to 13.

15. The light source module according to any one of claims 1 to 14 is provided. processing machine.

16. A processing method for processing a material using a combined laser beam emitted from a light source module, comprising the steps of: The light source module includes a plurality of semiconductor laser elements, The plurality of semiconductor laser elements include a first element group including one or more first semiconductor laser elements and emitting a first laser beam; a second element group including one or more second semiconductor laser elements and emitting a second laser beam; the combined laser beam includes at least one of the first laser beam and the second laser beam, The processing method includes: a control step of controlling power of each of the first laser light and the second laser light to maintain a combined wavelength, which is an average wavelength of the combined laser light, constant against a change in power of the combined laser light; when a power of the first laser light and a power of the second laser light are equal, an average wavelength of the first laser light is longer than an average wavelength of the second laser light, an average wavelength of the first laser light increases as the power of the first laser light increases; and In the control step, the power of each of the first laser light and the second laser light is controlled so that a ratio of the second laser light in the combined laser light increases as the power of the first laser light increases. Processing method.

17. When the power of the combined laser beam is a first power, the average wavelength of the first laser beam is λ11 and the combined wavelength is λt1; When the power of the combined laser light is a second power greater than the first power, the average wavelength of the first laser light is λ12 and the combined wavelength is λt2, λ12-λ11>λt2-λt1 holds The processing method according to claim 16.

18. The difference between the average wavelength of the first laser beam and the average wavelength of the second laser beam is 20 nm or less. The processing method according to claim 16 or 17.

19. The multiplexed wavelength is 400 nm or more and 500 nm or less. The processing method according to any one of claims 16 to 18.

20. The material includes Au or Cu. The processing method according to any one of claims 16 to 19.

21. In the control step, the material is irradiated with the combined laser light while changing the power of the combined laser light. The processing method according to any one of claims 16 to 20.

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