Light source device

Abstract

To provide a light source device that can be expected to sufficiently reduce speckle noise.SOLUTION: There is provided a light source device 1 that comprises a substrate 12, and laser light sources 100A, B including sub-mounts 40A, B mounted on the substrate 12 and semiconductor laser elements 30 mounted on the sub-mounts 40A, B, and the laser light sources 100A, B are arranged on the substrate 12 individually and independently, wherein the laser light sources 100A, B arranged adjacently and emitting light beams of the same wavelength band differ in heat resistance between the semiconductor laser elements 30 of the individual laser light sources 100A, B and substrate 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light source device equipped with a semiconductor laser. [Background technology]

[0002] Light source devices equipped with semiconductor lasers are used in various industrial fields. Among them, there are light source devices equipped with a plurality of semiconductor laser elements that emit light in the same wavelength band. Among them, a light source device has been proposed that includes a semiconductor laser array in which a plurality of semiconductor laser elements are horizontally arranged and integrally formed, and a heat sink in contact with the lower surface of the semiconductor laser array, and the material of the heat sink is different in the central region and the end region in the horizontal direction of the semiconductor laser array (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2015 / 063973 publication Summary of the Invention [Problem to be solved by the invention]

[0004] In the light source device described in Patent Document 1, the heat dissipation efficiency is non-uniform in the lateral direction of the semiconductor laser array, which broadens the wavelength width of the semiconductor laser elements and reduces speckle noise. However, since the heat sink material is simply different between the central region and the edge region of the semiconductor laser array, adjacent semiconductor laser elements are in contact with heat sinks made of the same material except for the areas where the material changes. Therefore, the heat dissipation efficiency of many adjacent semiconductor laser elements does not change much, and the wavelength of the emitted light does not change much either, so sufficient speckle noise reduction cannot be achieved.

[0005] The present disclosure has been made in consideration of the above problems, and aims to provide a light source device that can be expected to sufficiently reduce speckle noise. [Means for solving the problem]

[0006] In order to solve the above problem, a light source device according to one aspect of the present invention comprises: A substrate; a laser light source including a submount mounted on the substrate and a semiconductor laser element mounted on the submount; Equipped with a plurality of the laser light sources are individually and independently disposed on the substrate; The adjacently arranged laser light sources emitting light of the same wavelength band have different thermal resistances between the semiconductor laser elements and the substrates of the individual laser light sources. [Effects of the Invention]

[0007] As described above, the present disclosure can provide a light source device that can be expected to sufficiently reduce speckle noise. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a side view schematically showing a part of a light source device according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a side view schematically showing a part of a light source device according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a side view schematically showing a part of a light source device according to a third embodiment of the present invention. [Figure 4A] FIG. 10 is a side view schematically showing an example of an arrangement pattern of two types of laser light sources with different thermal resistances. [Figure 4B] FIG. 10 is a side view schematically showing an example of an arrangement pattern of three types of laser light sources with different thermal resistances. [Figure 4C] FIG. 10 is a side view schematically showing another example of an arrangement pattern of three types of laser light sources with different thermal resistances. [Figure 5A] FIG. 1 is a plan view schematically illustrating an example of a light source device including collimating lenses corresponding to the respective laser light sources. [Figure 5B]5B is a cross-sectional view taken along the line AA in FIG. 5A. [Figure 5C] 5B is a cross-sectional view of FIG. 5A. [Figure 5D] 5B is a cross-sectional view taken along the line CC in FIG. 5A. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments and examples for carrying out the present invention will be described with reference to the drawings. Note that the light source device described below is intended to embody the technical concept of the present invention, and unless otherwise specified, the present invention is not limited to the following. In each drawing, components having the same function may be assigned the same symbol. For convenience, the embodiments and examples may be shown separately to facilitate explanation or understanding of the main points, but partial substitution or combination of the configurations shown in different embodiments and examples is possible. In the following embodiments and examples, descriptions of matters common to the above will be omitted, and only the differences will be described. In particular, similar effects due to similar configurations will not be mentioned sequentially in each embodiment or example. The size and positional relationship of components shown in each drawing may be exaggerated to clarify the explanation.

[0010] (Light source device according to the first embodiment) First, a light source device according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a side view schematically showing a part of the light source device according to the first embodiment of the present invention.

[0011] The light source device 1 according to this embodiment includes a substrate 12, submounts 40 (specifically, 40A and 40B) mounted on the substrate 12, and laser light sources 100 (specifically, 100A and 100B) including semiconductor laser elements 30 mounted on the submounts 40 (40A and 40B), and the plurality of laser light sources 100 (100A and 100B) are individually and independently arranged on the substrate 12. In particular, the laser light sources 100A and 100B each include adjacently arranged semiconductor laser elements 30 that emit light of the same wavelength band, and the thermal resistance between the semiconductor laser elements 30 and the substrate 12 of each of the laser light sources 100A and 100B is different. 1 shows a region of the light source device 1 where two laser light sources 100A and 100B are arranged adjacent to each other, emitting light in the same wavelength band and having different thermal resistances between the semiconductor laser elements 30 and the substrate 12. In FIG. 1, each semiconductor laser element 30 emits laser light in the same wavelength band in a direction perpendicular to the plane of the drawing.

[0012] To describe the structure of the laser light sources 100A, 100B in more detail, the semiconductor laser element 30 and the submounts 40A, 40B are bonded together by a metal bonding layer 32, and the submounts 40A, 40B and the substrate 12 are bonded together by a metal bonding layer 42. Examples of materials for the metal bonding layers 32, 42 include gold-tin (AuSn), gold (Au), silver (Ag), copper (Cu), solder, and metal nanomaterials.

[0013] The thermal resistance between the semiconductor laser element 30 and the substrate 12 includes not only the thermal resistance of the submounts 40A and 40B but also the thermal resistance of the metal bonding layers 32 and 42. However, it is difficult to make the thermal resistance of the metal bonding layers 32 and 42 significantly different for each of the laser light sources 100A and 100B, and therefore, in order to change the thermal resistance between the semiconductor laser element 30 and the substrate 12, it is effective to change the thermal resistance of the submounts 40A and 40B.

[0014] In order to change the thermal resistance of the submounts 40A and 40B, in the first embodiment, the submount 40A of the laser light source 100A and the submount 40B of the laser light source 100B are made of different materials. Specifically, ceramic is used as the material for the submounts 40A and 40B, and in particular, aluminum nitride (AlN) is used as the material for the submount 40A, and silicon carbide (SiC) is used as the material for the submount 40B.

[0015] Both silicon carbide (SiC) and aluminum nitride (AlN) have high thermal conductivity, allowing efficient heat dissipation from the semiconductor laser element 30 to the substrate 12. Among them, the thermal conductivity of silicon carbide (SiC) is higher than that of aluminum nitride (AlN). Therefore, the thermal resistance between the semiconductor laser element 30 and the substrate 12 in the laser light source 100A having the submount 40A is higher than the thermal resistance in the laser light source 100B having the submount 40B.

[0016] In this way, in the laser light sources 100A and 100B that are arranged adjacent to each other and emit light in the same wavelength band, the thermal resistance between the semiconductor laser element 30 and the substrate 12 can be made different, which changes the heat dissipation state and makes it possible to make different the junction temperatures of the adjacent semiconductor laser elements 30. Therefore, by making the emission wavelengths of the adjacent laser light sources 100A and 100B different, speckle noise can be effectively suppressed.

[0017] As described above, in the first embodiment of the present invention, by changing the material of the submounts in adjacent laser light sources 100A and 100B that emit light in the same wavelength band, it is possible to change the thermal resistance between the semiconductor laser element 30 and the substrate 12 using submounts 40A and 40B of the same shape. Therefore, the optical design and manufacturing of the light source device 1 are easy, and the thermal resistance can be changed effectively at low manufacturing cost.

[0018] In this embodiment, a semiconductor laser element 30 that emits light of any wavelength from the ultraviolet region to the infrared region can be used. As long as at least two laser light sources that emit light in the same wavelength band and have different thermal resistances are arranged adjacent to each other, a light source device that emits light in one wavelength band or a light source device that emits light in multiple wavelength bands is possible.

[0019] The material for forming the submount 40 is not limited to the above materials, but may also be other ceramic materials such as alumina (Al2O3) and silicon nitride (Si3N4), as well as materials such as silicon and resin. In this embodiment, aluminum nitride (AlN) is used as the material of the substrate 12. However, the material is not limited to this, and other ceramic materials such as silicon carbide (SiC), alumina (Al2O3), and silicon nitride (Si3N4), resin materials, single crystals such as silicon, and metal materials with insulating layers can also be used.

[0020] (Light source device according to second embodiment) Next, a light source device according to a second embodiment of the present invention will be described with reference to Fig. 2. Fig. 2 is a side view schematically showing a part of the light source device according to the second embodiment of the present invention.

[0021] 2 shows a region of the light source device 1 where laser light sources 100C and 100D, which emit light in the same wavelength band and have different thermal resistances between the semiconductor laser elements 30 and the substrate 12, are arranged adjacent to each other. In FIG. 2 as well, each semiconductor laser element 30 emits laser light in the same wavelength band in the direction perpendicular to the paper surface. The second embodiment differs from the first embodiment in that adjacently arranged laser light sources 100C and 100D emitting light in the same wavelength band use submounts 40C and 40D with different thicknesses (height dimensions) to change the thermal resistance between the semiconductor laser element 30 and the substrate 12. The submounts 40C and 40D are made of the same material.

[0022] More specifically, this embodiment uses a submount 40C having a thickness T1 and a submount 40D having a thickness T2. Thickness T1 is greater than thickness T2, which makes the thermal resistance between the semiconductor laser element 30 and the substrate 12 in the laser light source 100C having the submount 40C greater than the thermal resistance in the laser light source 100D having the submount 40D.

[0023] In this embodiment, by adjusting the thicknesses of the submounts 40C and 40D, the difference in thermal resistance between the semiconductor laser element 30 and the substrate 12 in the adjacent laser light sources 100C and 100D that emit light in the same wavelength band can be easily and reliably adjusted. Other points are basically the same as those in the first embodiment, so further explanation will be omitted.

[0024] (Light source device according to the third embodiment) Next, a light source device according to a third embodiment of the present invention will be described with reference to Fig. 3. Fig. 3 is a side view schematically showing a part of the light source device according to the third embodiment of the present invention.

[0025] 3 shows a region of the light source device 1 where laser light sources 100E and 100F, which emit light in the same wavelength band and have different thermal resistances between the semiconductor laser elements 30 and the substrate 12, are arranged adjacent to each other. In FIG. 3 as well, each semiconductor laser element 30 emits laser light in the same wavelength band in the direction perpendicular to the paper surface. The third embodiment differs from the first and second embodiments in that adjacently arranged laser light sources 100E and 100F emitting light of the same wavelength band use submounts 40E and 40F with different areas in a plan view to change the thermal resistance between the semiconductor laser element 30 and the substrate 12. Both the submounts 40E and 40F are made of the same material.

[0026] More specifically, this embodiment uses a submount 40E with a width dimension W1 and a submount 40F with a width dimension W2. The width dimension W1 is smaller than the width dimension W2. The dimensions of the submounts 40E and 40F in the direction perpendicular to the width direction are the same, and the heat dissipation area of ​​the submount 40E is smaller than the heat dissipation area of ​​the submount 40F. Therefore, the thermal resistance between the semiconductor laser element 30 and the substrate 12 in the laser light source 100E having the submount 40E is larger than the thermal resistance in the laser light source 100D having the submount 40F.

[0027] In this embodiment, by adjusting the areas of the submounts 40E and 40F in a planar view, the difference in thermal resistance between the semiconductor laser element 30 and the substrate 12 in adjacent laser light sources 100E and 100F that emit light in the same wavelength band can be easily and reliably adjusted. Other points are basically the same as those in the first and second embodiments, so further explanation will be omitted.

[0028] As described above, according to the light source device 1 of the above embodiment, by varying the thermal resistance between the semiconductor laser elements 30 and the substrate 12 in adjacently arranged laser light sources 100 of the same wavelength, it is possible to change the heat dissipation state and vary the junction temperatures of the semiconductor laser elements 30 without adding any special components. This makes it possible to vary the emission wavelengths of adjacent laser light sources 100 and effectively suppress speckle noise. Therefore, it is possible to provide a light source device 1 that can be expected to sufficiently reduce speckle noise.

[0029] It can be said that the preferable range of the difference in thermal resistance between the semiconductor laser element 30 and the substrate 12 is 0.5° C. / W or more, which can reliably suppress the occurrence of speckle noise. In addition, when the wavelengths of the emitted light from adjacently arranged laser light sources 100 are different, there is little need to consider the occurrence of speckle noise, so a submount 40 with the same thermal resistance between the semiconductor laser element 30 and the substrate 12 can be used.

[0030] 1 to 3 show an example in which two types of submounts 40 with different thermal resistances are used, but if more laser light sources emitting light of the same wavelength are arranged adjacent to each other, any number of submounts 40 with different thermal resistances can be used. In that case, many types of submounts 40 with different thermal resistances can be used by combining the first to third embodiments described above. Furthermore, in addition to the submounts 40, the thermal resistances of the metal bonding layers 32, 42 can also be made different.

[0031] (Laser light source layout patterns with different thermal resistance) Next, with reference to FIGS. 4A to 4C, arrangement patterns of multiple types of laser light sources with different thermal resistances between the semiconductor laser elements and the substrate will be described. FIG. 4A is a side view schematically showing an example of an arrangement pattern using two types of laser light sources with different thermal resistances. FIG. 4B is a side view schematically showing an example of an arrangement pattern using three types of laser light sources with different thermal resistances. FIG. 4C is a side view schematically showing another example of an arrangement pattern using three types of laser light sources with different thermal resistances. All arrangement patterns show the case where 12 laser light sources emitting light in the same wavelength band are arranged adjacent to each other on the substrate 12. Note that in FIGS. 4A to 4C, the semiconductor laser elements and submounts are not individually shown, and the laser light sources are schematically shown as rectangles.

[0032] 4A shows an example in which two types of laser light sources 100P and 100Q, which have different thermal resistances between the semiconductor laser elements and the substrate 12, i.e., different thermal resistances of the submounts, are alternately arranged. With this arrangement, speckle noise can be efficiently suppressed with fewer types of submounts.

[0033] In the example shown in FIG. 4B, three types of laser light sources 100P, 100Q, and 100R with different thermal resistances are used, and the arrangement pattern of the laser light sources 100P, 100Q, and 100R is repeated in this order from left to right in the drawing. In the example shown in Figure 4C, three types of laser light sources 100P, 100Q, and 100R with different thermal resistances are used, and from the left to the right side of the drawing, an arrangement pattern of laser light sources 100P, 100Q, 100R in that order and an arrangement pattern of laser light sources 100Q, 100P, 100R in that order are repeated alternately.

[0034] In either example, an arrangement pattern is provided in which two or more types of laser light sources having different thermal resistances between the semiconductor laser element and the substrate, i.e., different thermal resistances of the submounts, are arranged adjacent to each other, and by repeating this arrangement pattern, it is possible to efficiently suppress speckle noise with a small number of submount types. Furthermore, by repeating the arrangement pattern of two or more types of laser light sources with different thermal resistances, it is possible to effectively suppress bias in color distribution due to the emission wavelengths of two or more types of light sources. The repeating arrangement pattern in which two or more types of laser light sources with different thermal resistances are arranged adjacent to each other is not limited to the above example, and any other arrangement pattern can be adopted.

[0035] (Light source device equipped with a collimating lens) Next, an example of a light source device equipped with collimating lenses corresponding to each laser light source according to the above embodiment will be described with reference to Figures 5A to 5D. Figure 5A is a plan view schematically showing an example of a light source device equipped with collimating lenses corresponding to each laser light source. Figure 5B is a cross-sectional view taken along line AA in Figure 5A, Figure 5C is a cross-sectional view taken along line BB in Figure 5A, and Figure 5D is a cross-sectional view taken along line CC in Figure 5A.

[0036] 5A to 5D, this light source device 1 has a package 10 composed of a substrate 12 and a sidewall 14, and a lens array 20 having a plurality of lens portions 22 arranged in a matrix. The lens array 20 is an integrally molded transparent glass member in which the plurality of lens portions 22 are connected by connecting portions 24. A main body portion 82 and a light-transmitting member 84 that seal the inside of the package 10 are arranged below the lens array 20.

[0037] A plurality of laser light sources 100, each including a semiconductor laser element 30 and a submount 40, and mirrors 50 corresponding to each laser light source 100 are mounted on the substrate 12. Power is supplied to each laser light source 100 from outside the package 10 via leads 90, wiring 60, and relay members 70. For ease of understanding, FIG. 5A shows the laser light source 100 including the semiconductor laser element 30 and submount 40 arranged below the upper leftmost lens portion 22 of the lens array 20 in a transparent manner.

[0038] The light source device 1 includes a plurality of laser light sources 100 that emit blue light, a plurality of laser light sources 100 that emit green light, and a plurality of laser light sources 100 that emit red light. The adjacently arranged laser light sources 100 that emit light of the same wavelength band of blue light, green light, or red light have different thermal resistances between the semiconductor laser elements 30 and the substrate 12 of the individual laser light sources 100. Any of the above-described embodiments can be employed to make the thermal resistances different.

[0039] The semiconductor laser element 30 of each laser light source 100 emits laser light in the horizontal direction, which is reflected in an approximately vertical direction by the corresponding mirror 50. The reflected light passes through the light-transmitting member 84, reaches the light incident surface LA of the lens array 20, passes through each lens portion 22, and is emitted as parallel light from the light exit surface LB of the lens array 20. The parallel light emitted from each lens portion 22 of the lens array 20 is focused by, for example, a focusing lens, and the light of each wavelength is combined. This makes it possible to emit white light with little speckle noise. Furthermore, in this embodiment, the laser light sources 100 are arranged independently, so that collimating lenses (lens portions) 22 corresponding to each laser light source 100 can be easily arranged.

[0040] In the above, the light source device 1 is shown in which the light from the laser light source 100 is reflected in a substantially vertical direction by the mirror 50, but this is not limited to this, and there is also a case where the light emitted in the horizontal direction from each laser light source 100 is emitted directly in the horizontal direction to the outside from the light source device without passing through a mirror. In the above, the case where a white light source is used is shown, but this is not limited to this, and there may be a light source device that emits light of a single wavelength in an arbitrary wavelength range, or a light source device that emits light in an arbitrary plurality of wavelength ranges.

[0041] Although the embodiments and modes of implementation of the present invention have been described, the disclosed contents may vary in the details of the configuration, and changes in the combination and order of elements in the embodiments and modes of implementation may be realized without departing from the scope and spirit of the claimed invention. [Explanation of symbols]

[0042] 1 Light source device 10 packages 12 PCB 14 Side wall 20 Lens Array 22 Lens section 24 Connection 30 Semiconductor laser element 40A~F submount 50 Mirror 60 wire 70 Relay parts 82 Main body 84 Translucent material 90 leads 100 laser light source LA light incident surface LB light exit surface

Claims

1. three or more laser light sources, each including a submount and a semiconductor laser element mounted on the submount; a substrate on which the three or more laser light sources are arranged in one direction, The three or more laser light sources include: one or more first laser light sources each including a first submount that is the submount and a first semiconductor laser element that is the semiconductor laser element; one or more second laser light sources each including a second submount that is the submount and a second semiconductor laser element that is the semiconductor laser element; one or more third laser light sources including a third submount that is the submount and a third semiconductor laser element that is the semiconductor laser element; Contains, the first laser light source, the second laser light source, and the third laser light source all emit light in the same wavelength band, but emit light in different emission wavelengths, thereby suppressing speckle noise; a light source device, wherein the one or more first laser light sources, the one or more second laser light sources, and the one or more third laser light sources are arranged on the substrate in a repeated arrangement pattern in which the first laser light source, the second laser light source, and the third laser light source are arranged in that order.

2. three or more laser light sources, each including a submount and a semiconductor laser element mounted on the submount; a substrate on which the three or more laser light sources are arranged in one direction, The three or more laser light sources include: one or more first laser light sources each including a first submount that is the submount and a first semiconductor laser element that is the semiconductor laser element; one or more second laser light sources each including a second submount that is the submount and a second semiconductor laser element that is the semiconductor laser element; one or more third laser light sources including a third submount that is the submount and a third semiconductor laser element that is the semiconductor laser element; Contains, the first laser light source, the second laser light source, and the third laser light source all emit light in the same wavelength band, but emit light in different emission wavelengths, thereby suppressing speckle noise; a light source device in which the one or more first laser light sources, the one or more second laser light sources, and the one or more third laser light sources are arranged on the substrate in a manner that a first arrangement pattern in which the first laser light source, the second laser light source, and the third laser light source are arranged in that order, and a second arrangement pattern in which the second laser light source, the first laser light source, and the third laser light source are arranged in that order are repeated alternately.

3. the three or more laser light sources include four or more of the laser light sources, The light emitting device according to claim 1 , wherein the one or more first laser light sources include two or more of the first laser light sources.

4. the three or more laser light sources include five or more laser light sources, the one or more first laser light sources include two or more of the first laser light sources, The light emitting device according to claim 1 , wherein the one or more second laser light sources include two or more second laser light sources.

5. the three or more laser light sources include six or more laser light sources, the one or more first laser light sources include two or more of the first laser light sources, the one or more second laser light sources include two or more second laser light sources, The light emitting device according to claim 1 , wherein the one or more third laser light sources include two or more third laser light sources.

6. The light emitting device according to claim 1 , wherein the light in the same wavelength band is any one of blue light, green light, and red light.

7. The light emitting device according to claim 1 , wherein the three or more laser light sources include a plurality of laser light sources that emit blue light, a plurality of laser light sources that emit green light, and a plurality of laser light sources that emit red light.

8. 8. The light emitting device according to claim 1, further comprising: a plurality of mirrors arranged on the substrate at positions away from the laser light sources in a direction perpendicular to a direction in which the three or more laser light sources are arranged in a top view.

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