WO2017135366A1

WO2017135366A1 - Semiconductor laser light source device

Info

Publication number: WO2017135366A1
Application number: PCT/JP2017/003749
Authority: WO
Inventors: 雅也吉野
Original assignee: ウシオ電機株式会社
Priority date: 2016-02-04
Filing date: 2017-02-02
Publication date: 2017-08-10
Also published as: JP6390920B2; CN108604766A; JP2017139355A

Abstract

A technique in PIV is provided which makes it possible to suppress reduction in accuracy of measurement results due to shadows of tracer particles. This semiconductor laser light source device is provided with a light source unit which includes multiple emitters arranged in a first direction, and a lens which converts the lasers emitted from the emitters so as to be parallel in a second direction. For each of the multiple emitters, the lens includes multiple lens regions which convert the lasers emitted from the respective emitters so as to be parallel in the second direction. In at least two of the multiple emitters and two lens regions corresponding to the two emitters, the positions in the second direction of the lens regions corresponding to the emitters are different with reference to the positions in the second direction of the respective emitters.

Description

Semiconductor laser light source device

The present invention relates to a semiconductor laser light source device.

Conventionally, a technique called PIV (Particle Image Velocimetry) is known as a method for measuring the flow and velocity of a fluid. PIV is a technology that visualizes and measures the flow of fluid by mixing fine particles called tracer particles in a fluid and photographing the scattered light obtained by irradiating the tracer particles with a sheet of laser light. is there.

For example, Patent Document 1 describes that an Nd: YAG laser is used as a PIV light source and laser light is converted into a sheet. Further, Patent Document 2 describes that an argon laser is used as a PIV light source, and the laser beam is incident on a rotating polygon mirror to scan in a sheet form.

JP 2007-085784 A JP 2010-117190 A

By the way, according to the earnest study of the present inventor, it has been found that the conventional PIV has the following problems. Hereinafter, a specific description will be given with reference to FIGS. 14A and 14B.

FIGS. 14A and 14B are schematic views showing sheet-like laser light L ′ generated by the light source device 200 in the conventional PIV. 14A is a diagram when the light source device 200 is viewed in the −x direction, and FIG. 14B is a diagram when the light source device 200 is viewed in the −y direction. The sheet-like laser beam L ′ irradiates the tracer particles 12. As shown in FIG. 14A, the sheet-like laser light L ′ travels while spreading in the y direction. Further, as shown in FIG. 14B, the sheet-like laser light L ′ has a certain width without spreading in the x direction.

Here, when the tracer particle 12 is irradiated, a shadow 13 is generated by the particle 12 (see FIGS. 14A and 14B). Therefore, the conventional PIV has a problem that the tracer particles 12a floating in the shadow 13 region cannot be observed, and the accuracy of the measurement result is lowered.

This invention aims at providing the technique which can suppress that the precision of a measurement result falls due to the shadow of a tracer particle | grain in PIV.

The semiconductor laser light source device of the present invention is
A semiconductor laser light source device that emits a laser sheet that spreads in a first direction and travels with a predetermined width in a second direction orthogonal to the first direction,
A light source unit including a plurality of emitters arranged in the first direction;
A lens for converting the laser beams emitted from the plurality of emitters in parallel in the second direction,
The laser sheet is formed by overlapping parallel light emitted from the lens,
The lens includes, for each of the plurality of emitters, a plurality of lens regions that convert the laser light emitted from the emitters in parallel in the second direction,
In at least two of the plurality of emitters and two lens regions corresponding to the two emitters, when the positions of the emitters in the second direction are used as a reference, the emitters The position of the lens region corresponding to is different in the second direction.

According to the above configuration, in at least two of the plurality of emitters and two lens regions corresponding to the two emitters, relative to the second direction of the emitter and the lens region corresponding to the emitter. The positional relationship is different. As a result, when laser light emitted from at least two emitters is converted into parallel light by the lens region, it proceeds at a predetermined angle without traveling in the same direction. As a result, it is possible to reduce the shadow area due to the tracer particles, and it is possible to suppress a decrease in the accuracy of the PIV measurement result.

In the above configuration,
In at least two of the lens regions of the plurality of lens regions,
The optical axis of one of the lens regions is higher than the emitter corresponding to one of the lens regions when viewed from a third direction orthogonal to both the first direction and the second direction. Is shifted in the direction of
The optical axis of the other lens region may be shifted in the direction opposite to the second direction with respect to the emitter corresponding to the other lens region when viewed from the third direction.

According to the above configuration, when laser light emitted from at least two emitters is converted into parallel light by the lens region, the laser light travels in a direction opposite to the optical axis. Thereby, the shadow area by the tracer particles can be further reduced, and the decrease in the accuracy of the PIV measurement result can be further suppressed.

In the above configuration,
The light source unit includes a semiconductor laser array in which a plurality of the emitters are arranged in the first direction, the first direction is a slow axis direction, and the second direction is a fast axis direction,
The semiconductor laser array may be curved so as to protrude in a direction opposite to the second direction when viewed from a third direction orthogonal to both the first direction and the second direction. I do not care.

According to the above configuration, the relative positional relationship in the second direction between the emitter and the lens region corresponding to the emitter is different in at least two emitters and the two lens regions corresponding to the two emitters. The form can be realized by bending the semiconductor laser array.

In the above configuration,
The light source unit includes a plurality of semiconductor laser elements including one emitter.
In at least two of the plurality of semiconductor laser elements, the positions in the second direction may be different from each other.

According to the above configuration, the relative positional relationship in the second direction between the emitter and the lens region corresponding to the emitter is different in at least two emitters and the two lens regions corresponding to the two emitters. The form can be realized by shifting the positions of the at least two semiconductor laser elements in the second direction.

In the above configuration,
Of the plurality of lens regions, the optical axes of at least two of the lens regions may be arranged so that the positions in the second direction are different from each other.

According to the above configuration, the relative positional relationship in the second direction between the emitter and the lens region corresponding to the emitter is different in at least two emitters and the two lens regions corresponding to the two emitters. The form can be realized by shifting the positions of the optical axes of the at least two lens regions in the second direction.

In the above configuration,
The optical axes of the plurality of lens regions are arranged in a straight line when viewed from a third direction orthogonal to both the first direction and the second direction,
The lens may be inclined at a predetermined angle from the first direction when viewed from the third direction.

According to the above configuration, the relative positional relationship in the second direction between the emitter and the lens region corresponding to the emitter is different in at least two emitters and the two lens regions corresponding to the two emitters. The form can be realized by inclining the lens by a predetermined angle from the first direction.

According to the semiconductor laser light source device of the present invention, it is possible to prevent the accuracy of the measurement result from being lowered due to the shadow of the tracer particles in the PIV.

It is a schematic diagram for demonstrating the outline | summary of PIV. It is a schematic diagram for demonstrating the semiconductor laser light source device of 1st embodiment. It is a schematic diagram for demonstrating the laser beam inject | emitted from a semiconductor laser array. It is a schematic diagram for demonstrating the semiconductor laser light source device of 1st embodiment. It is a schematic diagram for demonstrating the semiconductor laser light source device of 1st embodiment. It is a schematic diagram for demonstrating the semiconductor laser light source device of 1st embodiment. It is a schematic diagram for demonstrating the effect by the semiconductor laser light source device of 1st embodiment. It is a schematic diagram for demonstrating the semiconductor laser light source device of 2nd embodiment. It is a schematic diagram for demonstrating the semiconductor laser light source device of 2nd embodiment. It is a schematic diagram for demonstrating the semiconductor laser light source device of 3rd embodiment. It is a schematic diagram for demonstrating the semiconductor laser light source device of 3rd embodiment. It is a schematic diagram for demonstrating the semiconductor laser light source device of 4th embodiment. It is a schematic diagram for demonstrating the semiconductor laser light source device of 4th embodiment. It is a schematic diagram for demonstrating the conventional light source device. It is a schematic diagram for demonstrating the conventional light source device.

The semiconductor laser light source device of the embodiment will be described with reference to the drawings. In each figure, the dimensional ratio in the drawing does not necessarily match the actual dimensional ratio.

(First embodiment)
[Overview of PIV]
The semiconductor laser light source device 1 in the first embodiment will be described. The semiconductor laser light source device 1 is used as a light source for PIV (Particle Image Velocimetry). First, an outline of PIV will be described with reference to FIG.

As shown in FIG. 1, the semiconductor laser light source device 1 includes a semiconductor laser array 3. In FIG. 1, the longitudinal direction of the semiconductor laser array 3 is the y direction, the short direction of the semiconductor laser array 3 is the z direction, and the direction orthogonal to the y direction and the z direction is the x direction. The x direction corresponds to the “second direction”, the y direction corresponds to the “first direction”, and the z direction corresponds to the “third direction”.

The semiconductor laser light source device 1 emits a sheet-like laser beam LS. Hereinafter, the sheet-like laser light LS is referred to as “laser sheet LS”. The laser sheet LS is light that has a relatively small width in the x direction and travels while spreading in the y direction. As an example, the width of the laser sheet LS in the x direction is 1.8 to 2.5 mm or less in a region at least 1 to 2 m away from the semiconductor laser array 3 in the z direction. The laser sheet LS has a width of about 1 m in the y direction in a region at least 1 to 2 m away from the semiconductor laser array 3 in the z direction. That is, in this region, the width in the x direction is extremely small compared to the width in the y direction.

As will be described in detail later, the semiconductor laser light source device 1 includes a plurality of emitters that emit laser light L, and converts the laser light L emitted from each emitter into parallel light LP parallel to a specific direction (FIG. 1). reference). In this specification, “parallel light” is light that has a certain width (as an example, 1.5 mm) in the x direction and travels while spreading in the y direction. For convenience, FIG. 1 shows laser light L emitted from four emitters and parallel light LP that is light after the laser light is converted. Further, the laser light L emitted from one emitter and before being converted into parallel light is given a right oblique line, and the parallel light LP after being converted is given a left oblique line.

As shown in FIG. 1, the parallel light LP from each emitter overlaps each other to form a laser sheet LS. The laser sheet LS does not necessarily have to overlap light emitted from all the emitters, and may be formed by overlapping at least light emitted from a plurality of emitters.

The tracer particles 12 are mixed in the fluid to be measured. In FIG. 1, although the fluid itself is not illustrated, in a situation where a large number of tracer particles 12 are mixed in a predetermined fluid and the laser sheet LS is irradiated to this fluid, the laser sheet LS Only a part of the tracer particles 12 located in the region irradiated with is shown. The tracer particles 12 are, for example, fine particles made of resin such as polystyrene, fine droplets obtained by atomizing water and oil, plastic fine particles, smoke, and the like. When the laser sheet LS emitted from the semiconductor laser light source device 1 is irradiated onto the tracer particles 12 in the fluid, scattered light is generated.

The imaging device 14 images the scattered light from the tracer particles 12 and outputs the captured image to the image processing device 15. As an example, the imaging device 14 captures an image of 1000 frames per second. The image processing device 15 calculates the fluid velocity based on the input image. In addition, since the calculation method of the fluid velocity is a known technique (see, for example, Patent Document 1 and Patent Document 2 above), description thereof is omitted in this specification.

[Constitution]
Next, the configuration of the semiconductor laser light source device 1 will be described. As shown in FIG. 1, the semiconductor laser light source device 1 includes a semiconductor laser array 3, a submount 5, a heat sink 7, and a cylindrical lens 9. FIG. 1 is a schematic plan view of a semiconductor laser light source device 1 in which a submount 5 is disposed above a heat sink 7 and a semiconductor laser array 3 is disposed above the submount 5 when viewed from above. It is shown in the figure. Although not shown in FIG. 1, the semiconductor laser light source device 1 includes solder layers between the semiconductor laser array 3 and the submount 5 and between the submount 5 and the heat sink 7. The semiconductor laser array 3 corresponds to a “light source”, and the cylindrical lens 9 corresponds to a “lens”.

Hereinafter, the configuration of the semiconductor laser light source device 1 will be specifically described with reference to FIG.

FIG. 2 is a schematic diagram when the semiconductor laser light source device 1 of FIG. 1 is viewed in the left direction of the drawing, that is, in the −z direction. In FIG. 2, for the convenience of explanation, the cylindrical lens 9 has an outer edge.

The semiconductor laser array 3 includes a plurality of edge-emitting semiconductor laser elements arranged in an array. The semiconductor laser array 3 includes a side surface 30 that is a surface perpendicular to the z direction (corresponding to the xy plane in the drawing), and emits laser light from the side surface 30.

The semiconductor laser array 3 includes a plurality of emitters 31 arranged on the side surface 30 in the y direction. In the semiconductor laser array 3 shown in FIG. 2, the y direction that is the arrangement direction of the emitters 31 corresponds to the longitudinal direction of the semiconductor laser array 3. The emitter 31a is an emitter located at the center of the side surface 30 in the y direction. The emitter 31b is an emitter located at one end of the side surface 30 with respect to the y direction (ie, the end on the + y direction side), and the emitter 31c is the other end of the side surface 30 with respect to the y direction (ie, −y The emitter is located at the end of the direction side. As an example, the semiconductor laser array 3 includes 20 emitters 31 arranged at a pitch of 200 μm. In FIG. 2, nine emitters 31 are shown for convenience.

Hereinafter, the emitter 31a may be referred to as “center emitter 31a”, and the

emitters

31b and 31c may be referred to as “end emitter 31b” and “end emitter 31c”, respectively.

Each emitter 31 emits a laser beam that travels in both the x and y directions. FIG. 3 shows laser light L emitted from the central emitter 31 a of the semiconductor laser array 3. As shown in FIG. 3, the laser beam L diverges in both the x direction and the y direction. In addition, the laser light L diverges greatly in the x direction compared to the y direction. That is, the divergence angle in the x direction of the laser light L is larger than the divergence angle in the y direction. That is, the x direction corresponds to the “fast axis direction” and the y direction corresponds to the “slow axis direction”. The laser light emitted from the other emitters 31 travels in the same manner as the laser light L.

Referring back to FIG. The semiconductor laser array 3 is joined to the submount 5 by a solder layer 4. The solder layer 4 is placed on the upper surface of the submount 5. The semiconductor laser light source device 1 may not include the submount 5.

As shown in FIG. 2, the semiconductor laser array 3 is curved so as to approach the submount 5 from the end toward the center. In other words, the semiconductor laser array 3 is curved so as to protrude in the direction toward the submount 5 (that is, the −x direction). The reason why the semiconductor laser array 3 is curved in this way will be described later.

The temperature of the semiconductor laser array 3 rises as the laser beam is emitted. The submount 5 is made of a material having high thermal conductivity, and conducts heat generated from the semiconductor laser array 3 to the heat sink 7.

The solder layer 6 is placed on the upper surface of the heat sink 7 and joins the submount 5 and the heat sink 7.

The heat sink 7 releases the heat conducted from the submount 5 to the outside of the semiconductor laser light source device 1. The heat sink 7 is made of a metal having high thermal conductivity. The semiconductor laser light source device 1 may not include the heat sink 7.

The cylindrical lens 9 is disposed so as to collimate light in the x direction. Hereinafter, the cylindrical lens 9 will be described with reference to FIGS.

[Cylindrical lens]
FIG. 4 is a schematic diagram when the cylindrical lens 9 is viewed in the −z direction (see FIG. 1). In FIG. 4, for convenience of explanation, the emitter 31 located behind the cylindrical lens 9 (that is, on the −z direction side) is indicated by a broken line.

As shown in FIG. 4, the cylindrical lens 9 includes a plurality of lens regions 91 arranged in the y direction. In the present embodiment, the cylindrical lens 9 includes the same number of lens regions 91 as the emitter 31. Each lens region 91 faces each emitter 31. That is, the laser light emitted from each emitter 31 is incident on the lens region 91 that faces the laser beam.

Each lens region 91 has an optical axis OA parallel to the z direction. The optical axis OA is a straight line connecting the centers of the lens regions 91 and the focal points of the lens regions 91.

As described above, the semiconductor laser array 3 is curved so as to protrude in the direction toward the submount 5 (that is, the −x direction). Therefore, the position in the x direction of each emitter 31 is different from the position in the x direction of the optical axis OA of the lens region 91 corresponding to the emitter 31. Specifically, as shown in FIG. 4, the central emitter 31 a is greatly displaced in the −x direction from the optical axis OA of the corresponding lens region 91. Further, the

emitters

31b and 31c at the end portions are greatly shifted in the x direction from the optical axis OA of the corresponding lens region 91. Further, the emitter 31 positioned between the central emitter 31a and the

end emitters

31b and 31c is slightly shifted in the x direction or the −x direction from the optical axis OA of the corresponding lens region 91. As an example, the center emitter 31a and the

end emitters

31b and 31c are separated by 0.5 to 1.5 μm in the x direction. The lens region 91 corresponding to the central emitter 31a corresponds to “one lens region”, and the lens region 91 corresponding to the

end emitters

31b and 31c corresponds to “the other lens region”.

The lens region 91 converts the laser light L emitted from the opposing emitter 31 into parallel light LP. This will be specifically described with reference to FIGS.

FIG. 5 is a schematic cross-sectional view of the semiconductor laser light source device 1 of FIG. 1 taken along line AA. The line AA is parallel to the z direction and passes through the central emitter 31a (see FIG. 2) of the semiconductor laser array 3.

As shown in FIG. 5, the laser beam L spreads in the x direction and proceeds before entering the lens region 91. The lens region 91 converts the laser light L so as to have a certain width in the x direction. In other words, the lens region 91 suppresses the divergence of the laser light L in the x direction. Further, as shown in FIG. 1, the lens region 91 holds the divergence of the laser light L in the y direction. That is, the lens area 91 holds the divergence angle in the y direction of the laser light L. Thus, the lens region 91 converts the laser light L emitted from the opposing emitter 31a into parallel light LP having a constant width in the x direction and traveling in the y direction (FIGS. 1 and 5). reference).

In addition, as described above, converting the laser light so as to have a certain width without diverging in the x direction is expressed as “converting in parallel in the x direction”.

As described above with reference to FIG. 4, the central emitter 31a is positioned in the −x direction with respect to the optical axis OA of the corresponding lens region 91. Therefore, the parallel light LP obtained by converting the light emitted from the central emitter 31a travels at an angle θ1 (0.17 to 0.5 mrad as an example) with respect to the optical axis OA of the lens region 91. More specifically, the parallel light LP travels in the x direction with respect to the optical axis OA of the lens region 91.

FIG. 6 is a schematic cross-sectional view of the semiconductor laser light source device 1 of FIG. 1 taken along the line BB. The line BB is parallel to the z direction and passes through the emitter 31c (see FIG. 2) at the end of the semiconductor laser array 3.

As shown in FIG. 6, the lens region 91 converts the laser light L emitted from the opposing emitter 31c into parallel light LP having a certain width in the x direction and traveling while spreading in the y direction. As described above, the emitter 31c at the end is positioned in the x direction with respect to the optical axis OA of the corresponding lens region 91 (see FIG. 4). Therefore, the parallel light LP obtained by converting the light emitted from the emitter 31c at the end portion travels at an angle θ2 (0.17 to 0.5 mrad as an example) with respect to the optical axis OA of the lens region 91. More specifically, the parallel light LP travels in the −x direction with respect to the optical axis OA of the lens region 91.

The parallel light LP by the center emitter 31a and the end emitter 31c has been described with reference to FIGS. 5 and 6. Similarly, the parallel light LP by the other emitters 31 is also relative to the optical axis OA of the lens region 91. , Proceed at a predetermined angle.

As described above, the center emitter 31a and the

end emitters

31b and 31c are greatly displaced in the x direction or the −x direction from the optical axis OA of the corresponding lens region 91. Therefore, the converted parallel light LP travels at a relatively large angle (θ1, θ2) with respect to the optical axis OA (see FIGS. 5 and 6). On the other hand, the emitter 31 located between the central emitter 31a and the

end emitters

31b and 31c is slightly shifted from the optical axis OA of the corresponding lens region 91 in the x direction or the −x direction. Therefore, the converted parallel light LP travels at a relatively small angle with respect to the optical axis OA. Thus, the greater the deviation between the position of the emitter 31 and the position of the optical axis OA of the corresponding lens region 91, the greater the parallel light LP travels with respect to the optical axis OA.

[Reason for bending the semiconductor laser array]
Next, the reason why the semiconductor laser array 3 is curved as shown in FIG. 2 will be described.

The semiconductor laser array 3 and the submount 5 are superposed through the solder layer 4 melted by heating, and then bonded by the molten solder layer 4 being cured by cooling. Here, the semiconductor laser array 3 and the submount 5 are also heated / cooled together with the heating / cooling of the solder layer 4. At this time, the semiconductor laser array 3 and the submount 5 expand by heating and contract by cooling.

Here, the semiconductor laser array 3 and the submount 5 are made of different materials. Therefore, the thermal expansion coefficient of the material constituting the semiconductor laser array 3 and the thermal expansion coefficient of the material constituting the submount 5 are different. As an example, the semiconductor laser array 3 is made of GaAs, and the submount 5 is made of AlN. The thermal expansion coefficient of GaAs is 6.6 × 10 −6 / K, and the thermal expansion coefficient of AlN is 4.6 × 10 −6 / K. As described above, the thermal expansion coefficient of the semiconductor laser array 3 is larger than the thermal expansion coefficient of the submount 5. Therefore, as a result of the semiconductor laser array 3 contracting greatly as compared with the submount 5, the semiconductor laser array 3 is curved so as to protrude in the direction toward the submount 5 (ie, the −x direction) as shown in FIG.

[Function and effect]
Then, the effect by the semiconductor laser light source device 1 is demonstrated.

FIG. 7 is a schematic diagram of the semiconductor laser light source device 1 according to the first embodiment when the state in which the laser sheet LS is emitted is viewed in the −y direction. For the sake of convenience, only the parallel light LP from the central emitter 31a and the end emitter 31b (or the end emitter 31c) is shown in FIG. 7, and the parallel light LP from the other emitters 31 is not shown. In the following, for convenience of explanation, the parallel light LP from the central emitter 31a is referred to as “parallel light LP1”, and the parallel light LP from the end emitter 31b (or end emitter 31c) is referred to as “parallel light LP2”. Call.

As shown in FIG. 7, the fluid (not shown) and the tracer particles (12b, 12c, 12d, 12e) exist within a range away from the cylindrical lens 9 by a distance d. As an example, the distance d is 1 to 2 m.

The tracer particles (12b, 12c) exist in a region where the parallel light LP1 and the parallel light LP2 overlap. Therefore, the shadow of the tracer particles (12b, 12c) due to the parallel light LP1 is reduced by the parallel light LP2. Further, the shadow of the tracer particles (12b, 12c) due to the parallel light LP2 is reduced by the parallel light LP1. As a result, as shown in FIG. 7, the area of the shadow 13 by the tracer particles (12b, 12c) is relatively small.

On the other hand, the tracer particles (12d, 12e) exist in a region where the parallel light LP1 and the parallel light LP2 do not overlap. More specifically, the tracer particles (12d, 12e) exist in a region where each of the parallel light LP1 and the parallel light LP2 overlaps with another parallel light LP (not shown). For example, the parallel light LP1 overlaps the parallel light LP that travels more slowly in the −x direction than the parallel light LP2. Therefore, the shadow of the tracer particle 12d by the parallel light LP1 is reduced by the parallel light LP that travels while being gently inclined in the −x direction. Similarly, the parallel light LP2 overlaps the parallel light LP that travels more slowly in the x direction than the parallel light LP1. Therefore, the shadow of the tracer particle 12e due to the parallel light LP2 is reduced by the parallel light LP that travels while being gently inclined in the x direction. As a result, as shown in FIG. 7, the area of the shadow 13 due to the tracer particles (12d, 12e) is relatively small.

Thus, according to the semiconductor laser light source device 1 of the first embodiment, the area of the shadow 13 caused by the tracer particles 12 can be reduced as compared with the conventional light source device 200. That is, according to the semiconductor laser light source device 1 of the first embodiment, the tracer particles 12 that cannot be observed can be reduced, and the accuracy of PIV measurement results can be improved.

Further, as shown in FIG. 7, the parallel light LP1 from the central emitter 31a travels in the x direction, and the parallel light LP2 from the end emitter 31b travels in the −x direction. That is, the parallel light LP1 and the parallel light LP2 travel while being inclined in the opposite direction with respect to the optical axis OA (not shown). Therefore, the angle θ (that is, θ1 + θ2) formed by the parallel light LP1 and the parallel light LP2 becomes relatively large, so that the shadow caused by the tracer particles 12 can be further reduced.

(Second embodiment)
[Constitution]
Next, the semiconductor laser light source device 100 of the second embodiment will be described. The semiconductor laser light source device 100 of the second embodiment is different from the semiconductor laser light source device 1 of the first embodiment in that a plurality of semiconductor laser elements are provided instead of the semiconductor laser array 3, but the other configurations are as follows. It is the same. Hereinafter, the points of the second embodiment different from the first embodiment will be described with reference to FIGS.

FIG. 8 is a schematic view of the semiconductor laser light source device 100 according to the second embodiment when viewed in the −z direction (see FIG. 1). In FIG. 8, for the convenience of explanation, the cylindrical lens 9 has an outer edge.

As shown in FIG. 8, the semiconductor laser light source device 100 includes a plurality of semiconductor laser elements 103 instead of the semiconductor laser array 3. In FIG. 8, nine semiconductor laser elements 103 are shown as an example. The semiconductor laser elements 103 are arranged so that their positions in the x direction are different. Each semiconductor laser element 103 is bonded to the submount 5 by the solder layer 4. The plurality of semiconductor laser elements 103 correspond to a “light source unit”.

Each semiconductor laser element 103 includes one emitter 104. The emitter 104 emits laser light L that travels in the x and y directions (see FIG. 3).

Subsequently, the positions of the emitter 104 and the cylindrical lens 9 in the x direction will be described with reference to FIG. FIG. 9 is a schematic diagram when the cylindrical lens 9 of the semiconductor laser light source device 100 is viewed in the −z direction (see FIG. 1). In FIG. 9, for convenience of explanation, the emitter 104 located behind the cylindrical lens 9 (that is, on the −z direction side) is indicated by a broken line.

As shown in FIG. 9, each emitter 104 is arranged so as to face each lens region 91. That is, the laser light L emitted from each emitter 104 enters the opposing lens region 91 and is converted into parallel light LP (see FIGS. 5 and 6).

Further, as shown in FIG. 9, the position in the x direction is different between each emitter 104 and the optical axis OA of the lens region 91 corresponding to the emitter 104.

Specifically, the emitters (104a, 104b, 104c, 104g, 104i) are located in the x direction with respect to the optical axis OA of the corresponding lens region 91. Therefore, the parallel light LP from the emitters (104a, 104b, 104c, 104g, 104i) travels in the −x direction with respect to the optical axis OA of the lens region 91 (see FIG. 6). Note that the emitters (104a, 104b) are greatly displaced in the x direction from the optical axis OA of the lens region 91 as compared with the emitters (104c, 104g, 104i). Therefore, the parallel light LP from the emitters (104a, 104b) travels with a greater inclination in the -x direction than the parallel light LP from the emitters (104c, 104g, 104i).

The emitters (104d, 104e, 104f, 104h) are positioned in the −x direction with respect to the optical axis OA of the corresponding lens region 91. Therefore, the parallel light LP from the emitters (104d, 104e, 104f, 104h) travels in the x direction with respect to the optical axis OA of the lens region 91 (see FIG. 5). It should be noted that the emitters (104d, 104e) are greatly displaced in the −x direction from the optical axis OA of the lens region 91 as compared with the emitters (104f, 104h). Therefore, the parallel light LP from the emitters (104d, 104e) travels with a greater inclination in the x direction than the parallel light LP from the emitters (104f, 104h).

The semiconductor laser element 103 is loaded when it is bonded to the submount 5 by the solder layer 4. By changing the magnitude of the load applied to the semiconductor laser element 103, the position of the semiconductor laser element 103 in the x direction is adjusted. Alternatively, the position of the semiconductor laser element 103 in the x direction is adjusted by adjusting the amount of the solder layer 4. As an example, among the emitters 104a to 104i, the emitters (104a and 104b) positioned closest to the x direction and the emitters (104d and 104e) positioned closest to the −x direction are 0.5 to 1.. 5 μm away.

Also in the semiconductor laser light source device 100 of the present embodiment, for the same reason as the semiconductor laser light source device 1 of the first embodiment, the area of the shadow 13 by the tracer particles 12 can be reduced, and the accuracy of the PIV measurement result can be improved. The same applies to the following embodiments.

(Third embodiment)
[Constitution]
Next, the semiconductor laser light source device 110 of the third embodiment will be described. The semiconductor laser light source device 110 according to the third embodiment is different from the semiconductor laser light source device 1 according to the first embodiment in that the semiconductor laser array 3 is not curved and a lens 112 described later instead of the cylindrical lens 9. However, the other configurations are the same. Hereinafter, the points of the third embodiment different from the first embodiment will be described with reference to FIG.

FIG. 10 is a schematic view of the semiconductor laser light source device 110 according to the third embodiment when viewed in the −z direction (see FIG. 1). In FIG. 10, for the convenience of explanation, the outer edge of the lens 112 is shown. As shown in FIG. 10, the semiconductor laser light source device 110 includes a lens 112 instead of the cylindrical lens 9 (see FIG. 2). The semiconductor laser array 3 is not curved, and the emitters 31 are arranged in a straight line in the y direction.

FIG. 11 shows a schematic diagram when the lens 112 is viewed in the −z direction (see FIG. 1). In FIG. 11, for convenience of explanation, the emitter 31 positioned behind the lens 112 (that is, on the −z direction side) is indicated by a broken line.

As shown in FIG. 11, the lens 112 includes a plurality of lens regions 113. Each lens region 113 is arranged such that the position of the optical axis OA in the x direction is different. Specifically, the lens regions (113a, 113b, 113c, 113d, 113h, 113i) are arranged such that the optical axis OA is positioned in the x direction with respect to the corresponding emitter 31. Further, the lens regions (113e, 113f, 113g) are arranged so that the optical axis OA is positioned in the −x direction with respect to the corresponding emitter 31.

The parallel light LP from the emitter 31 corresponding to the lens regions (113a, 113b, 113c, 113d, 113h, 113i) is incident on the optical axis OA of each lens region 113 (113a, 113b, 113c, 113d, 113h, 113i). On the other hand, it travels in the x direction (see FIG. 5). In the lens areas (113a, 113b), the deviation between the position of the optical axis OA and the position of the emitter 31 is larger than in the lens areas (113c, 113d, 113h, 113i). Therefore, the parallel light LP from the emitter 31 corresponding to the lens regions (113a, 113b) travels with a greater inclination in the x direction than the parallel light LP from the emitter 31 corresponding to the lens regions (113c, 113d, 113h, 113i). To do.

Further, the parallel light LP from the emitter 31 corresponding to the lens regions (113e, 113f, 113g) travels in the −x direction with respect to the optical axis OA of the lens region 113 (see FIG. 6). In each lens region (113e, 113f, 113g), the optical axis OA and the corresponding emitter 31 are shifted by the same amount. Therefore, each parallel light LP from the emitter 31 corresponding to each lens region (113e, 113f, 113g) travels in the −x direction by the same angle. As an example, the optical axis OA of the

lens regions

113a and 113b and the optical axis OA of the

lens regions

113e, 113f, and 113g are separated by 0.5 to 1.5 μm in the x direction.

(Fourth embodiment)
[Constitution]
Subsequently, the semiconductor laser light source device 120 of the fourth embodiment will be described. The semiconductor laser light source device 120 of the fourth embodiment is different from the semiconductor laser light source device 1 of the first embodiment in that the semiconductor laser array 3 is not curved and in the direction of the cylindrical lens 9. Other configurations are the same. Hereinafter, the points of the fourth embodiment different from the first embodiment will be described with reference to FIG.

FIG. 12 is a schematic diagram of the semiconductor laser light source device 120 according to the fourth embodiment viewed in the −z direction (see FIG. 1). In FIG. 12, for the convenience of explanation, the outer edge of the cylindrical lens is shown. As shown in FIG. 12, in the semiconductor laser light source device 120, the cylindrical lens 9 is disposed at an angle φ (0.13 to 0.38 mrad as an example) with respect to the y direction. The semiconductor laser array 3 is not curved, and the emitters 31 are arranged in a straight line in the y direction. The angle φ corresponds to the “predetermined angle”.

FIG. 13 shows a schematic diagram when the cylindrical lens 9 is viewed in the −z direction (see FIG. 1). In FIG. 13, for convenience of explanation, the emitter 31 located behind the cylindrical lens 9 (that is, on the −z direction side) is indicated by a broken line.

As shown in FIG. 13, the position in the x direction differs between each emitter 31 and the optical axis OA of the lens region 91 corresponding to the emitter 31. Specifically, the lens regions (91a, 91b, 91c, 91d, 91e) are arranged such that the optical axis OA is positioned in the x direction with respect to the corresponding emitter 31. Further, the lens regions (91f, 91g, 91h, 91i) are arranged so that the optical axis OA is positioned in the −x direction with respect to the corresponding emitter 31. As an example, the optical axis OA of the lens region 91a and the optical axis OA of the lens region 91i are separated by 0.5 to 1.5 μm in the x direction.

Note that the parallel light LP from the emitter 31 corresponding to the lens regions (91a, 91b, 91c, 91d, 91e) travels in the x direction with respect to the optical axis OA of the lens region 91 (see FIG. 5). Further, the parallel light LP from the emitter 31 corresponding to the lens regions (91f, 91g, 91h, 91i) travels in the −x direction with respect to the optical axis OA of the lens region 91 (see FIG. 6).

Also, the optical axis OA of the lens region 91a is most greatly shifted in the x direction from the emitter 31b. Therefore, the parallel light LP from the emitter 31b travels with the greatest inclination in the x direction. Further, the optical axis OA of the lens area 91i is most greatly shifted in the −x direction from the emitter 31c. Therefore, the parallel light LP from the emitter 31c travels with the greatest inclination in the −x direction. In addition, the parallel light LP by the emitter 31 corresponding to the lens regions (91b, 91c, 91d, 91e, 91f, 91g, 91h) travels at a relatively small angle with respect to the optical axis OA.

(Another embodiment)
The semiconductor laser light source device is not limited to the configuration of the above-described embodiment, and it is needless to say that various modifications can be made without departing from the scope of the present invention. For example, it is needless to say that the configuration according to another embodiment below may be arbitrarily selected and adopted in the configuration according to the above-described embodiment.

<1> In the first embodiment and the second embodiment, the positions of the optical axes OA in the x direction of the lens areas 91 are the same, but the positions of the optical axes OA of the at least two lens areas 91 in the x direction are different. It doesn't matter. In the third embodiment and the fourth embodiment, the positions of the emitters 31 in the x direction are the same, but the positions of at least two emitters 31 in the x direction may be different.

Further, in one or a plurality of emitters (31, 104) of the first to fourth embodiments, the position of the emitter (31, 104) in the x direction and the lens region corresponding to the emitter (31, 104). The positions of (91, 113) in the x direction may coincide with each other.

Generally speaking, each emitter (31, 104) includes at least two emitters (31, 104) and at least two lens regions (91, 113) corresponding to the emitters (31, 104). When the position in the x direction is used as a reference, it can be expressed that the position of the corresponding lens region (91, 113) in the x direction is different.

<2> In the first to fourth embodiments, the emitter (31, 104) shifted in the x direction and the emitter (31, 104) shifted in the −x direction with respect to the optical axis OA of the lens region (91, 113). ) And is not limited to this. That is, all the emitters (31, 104) may be displaced in the x direction with respect to the optical axis OA of the lens regions (91, 113). Similarly, all the emitters (31, 104) may be displaced in the −x direction with respect to the optical axis OA. In other words, all the parallel light LP from each emitter (31, 104) may travel in an x-direction / −x-direction with respect to the optical axis OA.

<3> Further, although it has been described that the laser light L has a large divergence angle in the x direction and a small divergence angle in the y direction, the present invention is not limited thereto. That is, the laser light L may travel with the same divergence angle in the x direction and the y direction. Further, the laser beam L may travel with a small divergence angle in the x direction and a large divergence angle in the y direction.

<4> In the semiconductor laser light source device of the embodiment, a cylindrical lens is used as a lens for converting in parallel in the x direction (fast axis direction), but the present invention is not limited to this. For example, a fly-eye lens can be used in addition to the cylindrical lens. That is, any lens may be used as long as it is a lens that converts in parallel in the x direction (fast axis direction). For example, a lens that converts not only in the x direction (fast axis direction) but also in the y direction (slow axis direction) may be used.

<5> In the third embodiment, the lens region 113 may constitute one lens. That is, the lens 112 may be a lens group including a plurality of lenses.

1: Semiconductor laser light source device of the first embodiment 3: Semiconductor laser array 30: Side surface 31: Emitter 5: Submount 7: Heat sink 9: Cylindrical lens 91: Lens region 12: Tracer particle 13: Shadow 100: Second embodiment Semiconductor laser light source device 103: Semiconductor laser element of the second embodiment 104: Emitter of the second embodiment 110: Semiconductor laser light source device of the third embodiment 112: Lens of the third embodiment 113: Lens of the third embodiment Area 120: Semiconductor laser light source device of the fourth embodiment L: Laser light LP: Parallel light LS: Laser sheet OA: Optical axis

Claims

A semiconductor laser light source device that emits a laser sheet that spreads in a first direction and travels with a predetermined width in a second direction orthogonal to the first direction,
A light source unit including a plurality of emitters arranged in the first direction;
A lens for converting the laser beams emitted from the plurality of emitters in parallel in the second direction,
The laser sheet is formed by overlapping parallel light emitted from the lens,
The lens includes, for each of the plurality of emitters, a plurality of lens regions that convert the laser light emitted from the emitters in parallel in the second direction,
In at least two of the plurality of emitters and two lens regions corresponding to the two emitters, when the positions of the emitters in the second direction are used as a reference, the emitters A position of the lens region corresponding to the second region in the second direction is different.
In at least two of the lens regions of the plurality of lens regions,
The optical axis of one of the lens regions is higher than the emitter corresponding to one of the lens regions when viewed from a third direction orthogonal to both the first direction and the second direction. Is shifted in the direction of
The optical axis of the other lens region is shifted in a direction opposite to the second direction with respect to the emitter corresponding to the other lens region when viewed from the third direction. 2. The semiconductor laser light source device according to 1.
The light source unit includes a semiconductor laser array in which a plurality of the emitters are arranged in the first direction, the first direction is a slow axis direction, and the second direction is a fast axis direction,
The semiconductor laser array is curved so as to protrude in a direction opposite to the second direction when viewed from a third direction orthogonal to both the first direction and the second direction. The semiconductor laser light source device according to claim 1 or 2.
The light source unit includes a plurality of semiconductor laser elements including one emitter.
3. The semiconductor laser light source device according to claim 1, wherein positions of the semiconductor laser elements in the second direction are different from each other in at least two of the plurality of semiconductor laser elements.
3. The semiconductor laser according to claim 1, wherein optical axes of at least two of the lens regions are arranged so that positions in the second direction are different from each other. Light source device.
The optical axes of the plurality of lens regions are arranged in a straight line when viewed from a third direction orthogonal to both the first direction and the second direction,
3. The semiconductor laser light source device according to claim 1, wherein the lens is inclined by a predetermined angle from the first direction when viewed from the third direction. 4.