WO2017126035A1

WO2017126035A1 - Laser light source device and manufacturing method thereof

Info

Publication number: WO2017126035A1
Application number: PCT/JP2016/051450
Authority: WO
Inventors: 充輝二見; 一貴池田; 山本　修平; 矢部　実透
Original assignee: 三菱電機株式会社
Priority date: 2016-01-19
Filing date: 2016-01-19
Publication date: 2017-07-27

Abstract

The purpose of the present invention is to provide, in a laser light source device using a semiconductor laser array, a technique by which it is possible to reduce the influence of warpage of the semiconductor laser array and suppress the increase of residual stress as well as the deterioration of thermal resistance. A laser light source device 1 comprises a semiconductor laser array 10 which has a plurality of light emitting points, and a micro lens array 30 arranged on an optical axis of the light emitted from the semiconductor laser array 10. The semiconductor laser array 10 has a warpage of a concave or convex shape along an arrangement direction of the light emitting points. The micro lens array 30 is curved in the same direction as the warpage of the semiconductor laser array 10.

Description

Laser light source device and manufacturing method thereof

The present invention relates to a laser light source device using a semiconductor laser array and a manufacturing method thereof.

As a high-power semiconductor laser, it is common to use a semiconductor laser array in which a plurality of light emitting points are arranged in one bar. When using a semiconductor laser array, warpage along the arrangement direction of the light emitting points becomes a problem. In particular, in a long semiconductor laser array of several tens of W class, the influence of warpage on optical characteristics is serious.

The case where the semiconductor laser array has a convex warp along the arrangement direction of the light emitting points with the light emitting point at the center as an apex will be described. The microlens array arranged on the optical axis of the outgoing light of the semiconductor laser array has an optical working surface for collimating the fast axis direction on the incident side and an optical working surface for collimating the slow axis direction On the exit side. At this time, the warp causes a deviation between the optical axis of the light emitting point at the center of the semiconductor laser array and the optical axis of the light emitting point at the end. Therefore, when the light emitted from the semiconductor laser array passes through the microlens array, the light beam at the end is largely deflected.

In response to the above problem, for example, in Patent Document 1, a protrusion is provided at the end of the submount to suppress warpage that occurs when the semiconductor laser array is mounted on the submount or the heat sink. For example, in Patent Document 2, a semiconductor laser array having a warp is corrected by disposing and bonding submounts in which copper and tungsten are stacked above and below the semiconductor laser array.

International Publication No. 2010/131498 Japanese Patent Laid-Open No. 11-163467

However, with the technique described in Patent Document 1, there is a concern that the residual stress on the semiconductor laser array increases in exchange for suppressing the amount of warpage. Further, in the technique described in Patent Document 2, in addition to an increase in residual stress due to the correction of warpage, tungsten having a low thermal conductivity with respect to copper is disposed directly under the semiconductor laser array, so that there is a concern about deterioration of thermal resistance. .

Increase in residual stress has various effects on laser characteristics. For example, in the case of a red semiconductor laser array using GaAs as a substrate, if the residual stress in the compression direction increases near the interface with the submount or heat sink directly below it, the laser output decreases and the oscillation wavelength shifts to the short wavelength side. To do. Further, the residual stress increases the lattice defects in the active layer of the laser, leading to dark line degradation.

悪化 Deterioration of thermal resistance leads to increase of active layer temperature during laser oscillation, leading to deterioration of output characteristics. Further, when the laser is driven in a high temperature environment, a large cooling system such as water cooling by a chiller is required for the above reason. Therefore, the cost and size of the device incorporating the laser light source device are increased. Thus, it can be said that the active suppression of warping has a trade-off relationship with various effects due to an increase in residual stress or a deterioration in thermal resistance.

Accordingly, the present invention provides a technique capable of reducing the influence of warpage of a semiconductor laser array and suppressing an increase in residual stress and a deterioration in thermal resistance in a laser light source device using a semiconductor laser array. For the purpose.

A laser light source device according to the present invention includes a semiconductor laser array having a plurality of light emitting points, and a microlens array disposed on an optical axis of light emitted from the semiconductor laser array, and the semiconductor laser array emits the light emission The microlens array is curved in the same direction as the warp of the semiconductor laser array, having a concave or convex warp along the arrangement direction of the dots.

According to the present invention, a laser light source device includes a semiconductor laser array having a plurality of light emitting points, and a microlens array disposed on the optical axis of the emitted light of the semiconductor laser array. The microlens array is curved in the same direction as the warp of the semiconductor laser array.

Therefore, since the optical axis of the light emitting point of the semiconductor laser array and the optical axis of the microlens array are coaxial, the deflection of the light beam can be suppressed. Thereby, the influence of the warp of the semiconductor laser array can be reduced.

Also, since the allowable range of the warp amount of the semiconductor laser array is widened, it is possible to adopt a structure in which the residual stress of the semiconductor laser array is kept low and a structure with low thermal resistance. Thereby, increase of residual stress and deterioration of thermal resistance can be suppressed.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

It is a perspective view of the laser light source apparatus which concerns on embodiment. It is a perspective view of a submount. It is a perspective view of a micro lens array. It is the perspective view seen from another direction of the micro lens array. It is yz plane sectional drawing of a laser light source device. It is a graph which shows the temperature profile of the joining process in the manufacturing method of a laser light source device. It is a figure for demonstrating a mode that a laser light source apparatus warp in a joining process. It is a figure which shows the state with which the micro lens array was adhere | attached on the heat sink. It is a process block diagram of the manufacturing method of a laser light source device. It is a graph which shows the relationship between the curvature amount of a semiconductor laser array when a thickness of a heat sink is changed, and stress. It is a figure for demonstrating the influence which the curvature of a semiconductor laser array has on an optical characteristic in the laser light source apparatus which concerns on a premise technique. It is a figure for demonstrating the influence which the curvature of a semiconductor laser array has on an optical characteristic in the laser light source apparatus which concerns on a premise technique.

<Embodiment>
<Configuration>
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a laser light source device 1 according to an embodiment. For ease of explanation, xyz coordinate axes are appropriately shown in the drawing. Here, the + x direction and the −x direction are collectively referred to as an x-axis direction, the + y direction and the −y direction are collectively referred to as a y-axis direction, and the + z direction and the −z direction are collectively referred to as a z-axis direction.

The laser light source device 1 includes a semiconductor laser array 10, a submount 20, a microlens array 30, a heat sink 41, and a plate 42.

The semiconductor laser array 10 is a red semiconductor laser obtained by epitaxially growing an AlGaInP-based compound semiconductor on a GaAs substrate. The semiconductor laser array 10 is a broad area laser having two or more (plural) emission points, and each emission point has a wide stripe in the arrangement direction (x-axis direction) of the emission points. The resonator length (z-axis direction length) is 0.5 mm or more and 2.0 mm or less, and the lateral width (x-axis direction length) is 4 mm or more and 15 mm or less, which is a long dimension in the x-axis direction. The horizontal width is preferably optimized mainly by the output specifications of the laser light source device.

Generally, when a high output is required from one semiconductor laser array, more light emitting points are required, so the lateral width becomes longer. The laser light source device 1 according to the embodiment exerts a more remarkable effect in a long semiconductor laser array in which such a high output operation is expected. That is, the longer the horizontal width of the semiconductor laser array, the larger the amount of deviation of the light emitting point in the z-axis direction, and the greater the influence of warpage on the optical characteristics.

Further, the semiconductor laser array 10 has a convex warp along the arrangement direction of the light emitting points. Details of the convex warpage will be described later.

Next, the submount 20 will be described. FIG. 2 is a perspective view of the submount 20. As shown in FIG. 1, the semiconductor laser array 10 is bonded to one of two main surfaces facing each other along the epitaxial growth direction (x-axis direction). As shown in FIG. 2, the submount 20 includes a base material 21 and

conductive layers

22, 23, and 24, and is electrically connected by the semiconductor laser array 10, the

conductive layers

22 and 23, and the wires 25. As the base material 21, SiC or AlN having a linear expansion coefficient smaller than that of the heat sink 41 and higher thermal conductivity is used. Cu is used as a material for the

conductive layers

22, 23, and 24. The

conductive layers

22, 23, and 24 form a layer on the base material 21 by film formation by vacuum deposition or plating, or bonding by diffusion bonding or the like. Note that the conductive layer 24 is not intended to supply power, and is provided to suppress the warpage of the submount due to the difference in linear expansion coefficient between the base material 21 and the

conductive layers

22 and 23.

Next, the microlens array 30 will be described. FIG. 3 is a perspective view of the microlens array 30, and FIG. 4 is a perspective view of the microlens array 30 viewed from another direction. As shown in FIGS. 3 and 4, the microlens array 30 includes an optical action surface 31 and an optical action surface 32. The optical action surface 31 is a surface for collimating the fast axis (z-axis direction), and the optical action surface 32 is a surface for collimating the slow axis direction (x-axis direction). The optical action surface 31 is provided on the side close to the semiconductor laser array 10, and the optical action surface 32 is provided on the side facing the optical action surface 31 (that is, the side far from the semiconductor laser array 10).

Further, as shown in FIG. 1, the microlens array 30 has a convex curve along the arrangement direction of the light emitting points. That is, the microlens array 30 is curved in the same direction as the warp of the semiconductor laser array 10.

As shown in FIGS. 3 and 4, the optical action surface 31 is a cylindrical lens array, and the optical action surface 32 is a cylindrical lens array rotated by 90 ° with respect to the optical action surface 31. Each cylindrical lens array is composed of at least as many cylindrical lenses as the light emitting points of the semiconductor laser array 10. The cylindrical lens array on the optical action surface 31 is arranged so that the optical axis of each cylindrical lens is coaxial with the optical axis of the light emitting point of the corresponding semiconductor laser array 10. Thereby, even if the light emitting points of the semiconductor laser array 10 have shifted in the z-axis direction, the optical axis of the cylindrical lens is coaxial with respect to the respective light emitting points, so that the deflection of the light beam can be suppressed. In the cylindrical lens array on the optical action surface 32, each cylindrical lens is arranged at the same interval as the light emitting points of the semiconductor laser array 10.

Next, the heat sink 41 will be described. As shown in FIG. 1, the heat sink 41 is bonded to the surface of the submount 20 that faces the surface to which the semiconductor laser array 10 is bonded. More specifically, the heat sink 41 is solder-bonded to the submount 20 via the plate 42, and a surface facing the surface bonded to the plate 42 is a cooling surface. As a material for the heat sink 41 and the plate 42, Cu or Al having a high thermal conductivity is used to reduce the thermal resistance. FIG. 5 is a yz plane sectional view of the laser light source device 1. As shown in FIG. 5, the plate 42 is inserted for the purpose of height adjustment for securing a space when the microlens array 30 is arranged in front of the semiconductor laser array 10 (+ y direction). For this reason, the plate 42 is disposed at a position where it does not interfere with the microlens array 30, and is further disposed along the emission end face of the semiconductor laser array 10 as shown in FIG.

In such a configuration, the heat exhaust path of the heat generated near the emission end face of the semiconductor laser array 10 during heat generation during the laser operation is limited to the direction excluding the microlens array 30 side. Therefore, from the viewpoint of lowering the thermal resistance, it is necessary to ensure that the plate 42 has a space for arranging the microlens array 30 and is made as thin as possible so as to transfer heat to the heat sink 41 as soon as possible. Further, Cu or Al as the material of the heat sink 41 and the plate 42 has a large linear expansion coefficient with respect to GaAs as the material of the semiconductor laser array 10 or SiC or AlN as the main material of the submount 20. Therefore, from the viewpoint of reducing the residual stress of the semiconductor laser array 10, it is desirable to reduce the total thickness of the heat sink 41 and the plate 42 as much as possible.

<Manufacturing method>
Next, regarding the method of manufacturing the laser light source device 1 according to the embodiment, the assembly of the components will be described in particular. The laser light source device 1 according to the present embodiment is characterized in that the semiconductor laser array 10, the submount 20, the heat sink 41, and the plate 42 are joined by a single heating and pressing process using solder. As the solder used at the time of joining, it is desirable to use AuSn solder having excellent reliability and thermal conductivity. The melting point of the AuSn solder varies depending on the ratio of Au and Sn, but is approximately 300 ° C. or higher and 340 ° C. or lower.

FIG. 6 is a graph showing a temperature profile of the bonding process in the method for manufacturing the laser light source device 1, and FIG. 7 is a diagram for explaining how the laser light source device 1 is warped in the bonding process. Note that states 1 to 3 in FIG. 7 indicate states of the laser light source device 1 in the range of states 1 to 3 indicated by the range of arrows in the temperature profile of FIG.

First, the semiconductor laser array 10, the submount 20, the heat sink 41, and the plate 42 are arranged at positions that are bilaterally symmetrical with respect to the center in the arrangement direction of the light emitting points in plan view. State 1 in FIG. 7 shows a state in which each member is not warped before joining. Since the temperature and load are uniformly applied when the members come in contact with each other at the time of heating and pressurization, it is desirable that each component before joining has no warp or has a small warp as in State 1.

Next, the semiconductor laser array 10, the submount 20, the heat sink 41, and the plate 42 are joined by performing one heating and pressurization using solder. State 2 in FIG. 7 shows a state in which each member is attached at a high temperature exceeding the melting point of the solder in the heating and pressurizing steps. Since the solder is a liquid above the melting point, the contact interfaces are not constrained to each other and no stress is generated. In order to uniformly apply the temperature to each member, the heating is performed from both directions of the upper surface of the semiconductor laser array 10 and the lower surface of the heat sink 41. Moreover, in order to prevent the position shift of each member, it is necessary to apply the pressure before exceeding the melting point of the solder. After the heating and pressurizing steps for a predetermined time, the temperature is lowered and the pressure is released, but pressure is applied until the temperature falls below the melting point of the solder for the reason described above.

Next, the semiconductor laser array 10, the submount 20, the heat sink 41, and the plate 42 are cooled to a temperature below the melting point of the solder, and a convex warp is generated along the arrangement direction of the light emitting points with respect to the semiconductor laser array 10. . State 3 in FIG. 7 shows a state where the cooling has progressed to a temperature below the melting point of the solder through the heating and pressurizing steps. Solder has changed to a solid state, and each member is constrained at each joint interface. Accordingly, thermal stress is generated from the difference in linear expansion coefficient of each member, and increases as the temperature decreases starting from the melting point of the solder. At this time, the linear expansion coefficient of Cu, which is the main material of the heat sink 41 and the plate 42, is compared to the linear expansion coefficient of GaAs, which is the main material of the semiconductor laser array 10 (5.7 × 10 ⁻⁶ / ° C. at room temperature). 16.8 × 10 ⁻⁶ / ° C. at room temperature) is very large. Therefore, each member is warped as in state 3 in FIG. Note that, in state 3 in FIG. 7, the actual warpage amount and the scale of each member are different in order to emphasize the warpage.

In the method of manufacturing the laser light source device 1 according to the embodiment, the semiconductor laser array 10, the submount 20, the plate 42, and the heat sink 41 are symmetrically positioned with respect to the center in the arrangement direction of the light emitting points in plan view. Placed in. That is, by joining these members so as to be bilaterally symmetric with respect to the arrangement direction of the light emitting points, the thermal stress after joining is generated uniformly in the left and right directions, and the warped shape is also bilaterally symmetric. Therefore, the coupling efficiency between the emitted light of the semiconductor laser array 10 and the curved microlens array 30 is stabilized. The axis of symmetry at this time is shown as an axis 100 in FIG. Note that the amount or shape of the warp generated in the state 3 in FIG. 7 varies depending on the material or size of the submount 20, the heat sink 41, and the plate 42.

Next, the microlens array 30 curved in the same direction as the warp of the semiconductor laser array 10 is bonded to the heat sink 41 via an adhesive on the optical axis of the emitted light of the semiconductor laser array 10. This will be specifically described below. After the joining process of each member, the microlens array 30 is aligned and then adhered to the heat sink 41. FIG. 8 is a diagram illustrating a state where the microlens array 30 is bonded to the heat sink 41. The microlens array 30 is aligned by active alignment, and the microlens array 30 is bonded to the heat sink 41 using an epoxy adhesive 51. Curing of the adhesive 51 is performed in two stages, and after the temporary curing by ultraviolet irradiation immediately after the bonding, a heat treatment process is performed to thermally cure.

In general, epoxy-based adhesives have a large linear expansion coefficient (50 × 10 ⁻⁶ / ° C. or more and 100 × 10 ⁻⁶ / ° C. or less), so that the lens moves and condenses as the operating temperature of the laser light source device changes. There is concern about the deterioration of sex. On the other hand, in the embodiment, the amount of the epoxy adhesive 51 arranged between the microlens array 30 and the heat sink 41 is adjusted so that the thickness of the plate 42 is the minimum necessary thickness. ing. Therefore, the displacement of the microlens array 30 is minimized. Further, as shown in FIG. 8, by applying an epoxy adhesive 51 only to a partial region of the microlens array 30, the lens of the microlens array 30 and the heat sink 41 are caused by a difference in linear expansion coefficient. Prevents cracking or adhesive peeling.

In addition to the above processes, there is a wiring process for power supply. Since the microlens array 30 is actively aligned, the wiring process of the laser light source device 1 according to the embodiment is performed between the solder bonding process and the bonding and curing process of the microlens array. The wiring process includes wire bonding for supplying power from the submount 20 to the semiconductor laser array 10 and ribbon bonding for supplying power from the lead material to the submount 20. Then, the laser light source device 1 and the external power source are electrically connected via the lead material. In order to improve reliability, the above structure may be hermetically sealed using a cap or a lid. The process described above is shown as a process block diagram in FIG. FIG. 9 is a process block diagram of the method for manufacturing the laser light source device 1.

<Effect>
Next, the effects obtained from the laser light source device 1 according to the embodiment and the manufacturing method thereof will be described in comparison with the base technology.

First, the prerequisite technology will be explained. 11 and 12 are diagrams for explaining the influence of the warp of the semiconductor laser array 101 on the optical characteristics in the laser light source device according to the base technology.

As shown in FIG. 11, the semiconductor laser array 101 has a convex warp along the arrangement direction of the light emitting points with the light emitting point at the center as the apex. Further, the microlens array 102 disposed on the optical axis of the emitted light of the semiconductor laser array 101 has an optical working surface for making the fast axis direction parallel light on the incident side and makes the slow axis direction parallel light. The optical action surface is provided on the exit side. At this time, the warp causes a deviation between the optical axis 201 of the light emitting point at the center of the semiconductor laser array 101 and the optical axis 202 of the light emitting point at the end. Therefore, as shown in FIG. 12, there is a problem that when the light emitted from the semiconductor laser array 101 passes through the microlens array 102, the light beam at the end is largely deflected.

On the other hand, the laser light source device 1 according to the embodiment includes a semiconductor laser array 10 having a plurality of light emitting points, and a microlens array 30 disposed on the optical axis of emitted light from the semiconductor laser array 10. The semiconductor laser array 10 has a convex warp along the arrangement direction of the light emitting points, and the microlens array 30 is curved in the same direction as the warp of the semiconductor laser array 10.

The method of manufacturing the laser light source device 1 includes a semiconductor laser array 10 having a plurality of light emitting points, a submount 20 disposed on one of two main surfaces facing each other along the epitaxial growth direction of the semiconductor laser array 10, The heat sink 41 disposed on the surface opposite to the surface on which the semiconductor laser array 10 is disposed in the submount 20, and the plate 42 disposed between the heat sink 41 and the submount 20, respectively, have a light emitting point in plan view. The step (a) of arranging the semiconductor laser array 10, the submount 20, the heat sink 41, and the plate 42 is performed by performing a step (a) of arranging the semiconductor laser array 10 at a symmetrical position with respect to the center in the arrangement direction and one heating and pressurization using solder. Bonding step (b), semiconductor laser array 10, submount 20, heat sink 41 And the step (c) of cooling the plate 42 to a temperature equal to or lower than the melting point of the solder to generate a convex warp along the arrangement direction of the light emitting points with respect to the semiconductor laser array 10, and the warp of the semiconductor laser array 10. A step (d) of adhering the microlens array 30 curved in the direction to the heat sink 41 via an adhesive on the optical axis of the emitted light of the semiconductor laser array 10.

Therefore, since the optical axis of the light emitting point of the semiconductor laser array 10 and the optical axis of the microlens array 30 are coaxial, the deflection of the light beam can be suppressed. Thereby, the influence of the curvature of the semiconductor laser array 10 can be reduced.

Further, since the allowable range of the warp amount of the semiconductor laser array 10 is widened, it is possible to adopt a structure in which the residual stress of the semiconductor laser array 10 is kept low and a structure with low thermal resistance. Thereby, increase of residual stress and deterioration of thermal resistance can be suppressed. Therefore, the durability of the laser light source device 1 is improved.

Further, since it is not necessary to suppress the warp of the semiconductor laser array 10 for the purpose of suppressing the deterioration of the condensing characteristic, an additional member for suppressing the warp is unnecessary, and the suppression of the deterioration of the condensing characteristic is further inexpensive. Can be done.

In addition, the method of suppressing the warp of the semiconductor laser array by providing a convex portion at the end of the submount requires two submounts, which increases the manufacturing cost of the laser light source device. Since only one form is required, there is no such problem.

Here, the relationship between the amount of warpage of the semiconductor laser array 10 and the stress when the thickness of the heat sink 41 is changed will be described. FIG. 10 is a graph showing the relationship between the amount of warpage of the semiconductor laser array 10 and the stress when the thickness of the heat sink 41 is changed. SiC is used as the base material of the submount 20 and Cu is used as the material of the heat sink 41 and the plate 42. The horizontal axis indicates the thickness of the heat sink 41 of the reference structure as 1, and the vertical axis indicates the warpage amount and the stress value in the reference structure as 1, respectively. The warping amount is the absolute value of the difference between the central portion and the end portion of the semiconductor laser array 10, and the stress is the absolute value of the stress at the lower surface of the semiconductor laser array 10. It is an analysis result under the condition that there is no change. From FIG. 10, it can be seen that increasing the thickness of the heat sink 41 reduces the amount of warping while increasing the stress.

As described above, in the laser light source device 1, the influence of the deterioration of the optical characteristics due to the warp of the semiconductor laser array 10 can be absorbed by the curvature of the microlens array 30, and the heat sink that has been conventionally limited by the warp is thin, It is possible to employ a structure with a small residual stress. In addition, by making the heat sink 41 thinner, the distance from the semiconductor laser array 10 that is the heat source of the laser light source device 1 to the cooling surface of the heat sink 41 can be shortened, and the thermal resistance as the laser light source device 1 is reduced. Leads to.

The submount 20 is bonded to one of two main surfaces facing each other along the epitaxial growth direction of the semiconductor laser array 10, and is bonded to the surface of the submount 20 facing the surface to which the semiconductor laser array 10 is bonded. The semiconductor laser array 10, the submount 20, and the heat sink 41 are respectively disposed at positions symmetrical with respect to the center in the arrangement direction of the light emitting points in plan view.

Therefore, by stably making the warped shape bilaterally symmetrical with respect to the center of the light emitting points in the arrangement direction, the shape of the corresponding microlens array 30 is also made symmetrical with respect to the center of the light emitting points in the arrangement direction. be able to. Thereby, the optical axis of each light emission point and the optical axis of each microlens of the optical action surface 31 can be stably made coaxial.

Since there is a step on the surface of the heat sink 41 where the submount 20 is bonded, the height of the optical axis with the semiconductor laser array 10 can be adjusted when the microlens array 30 is directly bonded to the heat sink 41. That is, the height of the optical axis can be adjusted only by directly bonding the microlens array 30 to the heat sink 41. Therefore, the optical axis alignment of the microlens array 30 is facilitated.

Since the step is formed by the plate 42 disposed between the heat sink 41 and the submount 20, the height of the optical axis can be adjusted by adjusting the thickness of the plate 42.

Since the microlens array 30 is bonded to the heat sink 41 via the adhesive 51, the height of the optical axis can be adjusted only by directly bonding the microlens array 30 to the heat sink 41. Therefore, the optical axis alignment of the microlens array 30 is facilitated.

Further, in the method of manufacturing the laser light source device 1, the semiconductor laser array 10, the submount 20, the heat sink 41, and the plate 42 are arranged symmetrically with respect to the center in the arrangement direction of the light emitting points in plan view, and soldered together. Therefore, the warpage of the semiconductor laser array 10 after the bonding can be stably made to be a left-right symmetrical curve shape with respect to the center in the arrangement direction of the light emitting points. On the other hand, when a plurality of times of bonding are performed instead of batch bonding, a pressurizing process is required one by one, and it becomes difficult to control the warped shape after bonding.

In addition, in the case of an asymmetrical arrangement with respect to the center of the light emitting point in the arrangement direction, the thermal stress after soldering is not uniform with respect to the center of the light emitting point in the arrangement direction. It becomes asymmetrical with respect to the center in the arrangement direction. In contrast, by making the warp shape of the semiconductor laser array 10 stably symmetrical with respect to the center of the light emitting point arrangement direction, the shape of the corresponding microlens array 30 is similarly the center of the light emitting point arrangement direction. Can be symmetrical. Further, the optical axis of each light emitting point and the optical axis of each microlens on the optical action surface 31 can be stably coaxial.

The plate 42 may have a structure integrated with the heat sink 41 in advance. For example, by providing a step corresponding to the thickness of the plate 42 to the heat sink 41 by cutting or pressing, the same effect as in the case of the embodiment can be obtained.

Further, the semiconductor laser array 10 is not limited to the material or the oscillation wavelength described in the embodiment. That is, the same effect as in the case of the embodiment can be obtained even in a semiconductor laser array using InP, GaN, sapphire or the like as an initial growth substrate.

Further, the semiconductor laser array 10 is not limited to the convex warp shape described in the embodiment. That is, a concave warpage shape may be used, and an effect equivalent to that of the embodiment can be obtained as long as the structure can stably generate the same warpage regardless of the amount of warpage.

Further, the microlens array 30 is not limited to the arrangement of the optical action surfaces 31 and 32. That is, a microlens array having a shape in which the optical action surface 31 does not have a lens surface for incident light and the optical action surface 32 acts in the fast axis direction and the slow axis direction, or the optical action surface 31 is a fast axis. Even in the case of a microlens array having a shape that acts in the direction and the slow axis direction and the optical action surface 32 does not have a lens surface with respect to incident light, the same effect as in the case of the embodiment can be obtained.

Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

In the present invention, the embodiments can be appropriately modified or omitted within the scope of the invention.

1 laser light source device, 10 semiconductor laser array, 20 submount, 30 microlens array, 41 heat sink, 42 plate, 51 adhesive.

Claims

A semiconductor laser array (10) having a plurality of light emitting points;
A microlens array (30) disposed on the optical axis of the emitted light of the semiconductor laser array (10);
With
The semiconductor laser array (10) has a concave or convex warp along the arrangement direction of the light emitting points,
The microlens array (30) is a laser light source device that is curved in the same direction as the warp of the semiconductor laser array (10).
A submount (20) joined to one of two main surfaces facing each other along the epitaxial growth direction of the semiconductor laser array (10);
A heat sink (41) bonded to a surface facing the surface to which the semiconductor laser array (10) is bonded in the submount (20);
Further comprising
The said semiconductor laser array (10), the said submount (20), and the said heat sink (41) are respectively arrange | positioned in the left-right symmetric position with respect to the center of the arrangement direction of the said light emission point in planar view. Laser light source device.
The laser light source device according to claim 2, wherein the heat sink (41) has a step on a surface to which the submount (20) is joined.
The laser light source device according to claim 3, wherein the step is formed by a plate (42) disposed between the heat sink (41) and the submount (20).
The laser light source device according to claim 3, wherein the microlens array (30) is bonded to the heat sink (41) via an adhesive (51).
The laser light source device according to claim 4, wherein the microlens array (30) is bonded to the heat sink (41) via an adhesive (51).
(A) a semiconductor laser array (10) having a plurality of light emitting points, a submount (20) disposed on one of two main surfaces facing each other along the epitaxial growth direction of the semiconductor laser array (10), A heat sink (41) disposed on a surface facing the surface on which the semiconductor laser array (10) is disposed in the submount (20), and disposed between the heat sink (41) and the submount (20). Each of the plates (42) to be arranged at positions symmetrical with respect to the center in the arrangement direction of the light emitting points in plan view;
(B) performing a single heating and pressurization using solder to join the semiconductor laser array (10), the submount (20), the heat sink (41), and the plate (42);
(C) The semiconductor laser array (10), the submount (20), the heat sink (41) and the plate (42) are cooled to a temperature below the melting point of the solder, and the semiconductor laser array (10) Generating a concave or convex warp along the arrangement direction of the light emitting points;
(D) A microlens array (30) that curves in the same direction as the warp of the semiconductor laser array (10) is placed on the heat sink (41) via an adhesive on the optical axis of the emitted light of the semiconductor laser array (10). A process of adhering to
A method of manufacturing a laser light source device.