JP2017010636A - LD light source device and light source device - Google Patents

Abstract

An LD light source device in which a distance between central axes of a light beam by a laser beam emitted from a laser diode (LD) is two-dimensionally compressed, a structure is simple, and the device can be miniaturized, and a light source provided with the LD light source device Providing equipment. A plurality of LD arrays in which a plurality of LDs that emit laser light are arranged apart from each other in the x direction, a light source unit that is arranged apart from each other in the y direction, and a laser emitted from each of the LDs. And a compression optical system 20 that two-dimensionally compresses the distance between the central axes of the light beams by light. The compression optical system is composed of an integral prism, and corresponds to a light incident surface facing the LD and an LD group 14 composed of a plurality of LDs arranged in the y direction, and a plurality of light reflections for reflecting a light beam bundle of laser light in the x direction. A primary reflection mechanism 25 composed of a surface and a secondary reflection mechanism 30 that compresses the distance between the central axes of the light beams from the primary reflection mechanism in the y direction. [Selection] Figure 1

Description

  The present invention relates to an LD light source device including a plurality of LDs and a light source device including the LD light source device.

In recent years, in light source devices, LD (laser diode) or the like is used as a light source in response to demands for energy saving and downsizing. As an LD light source device having such an LD, in order to increase output, a light source unit in which a plurality of LDs are arranged vertically and horizontally, and the distance between the central axes of the beam bundles of laser beams from each LD are set. An apparatus including a compression optical system for compression is known (see Patent Document 1). The compression optical system in this LD light source device is composed of two step-like mirrors each having a plurality of light reflecting surfaces arranged in a step shape.
According to such an LD light source device, since the distance between the central axes of the beam bundles of the laser beams from the respective LDs is compressed by the compression optical system, the light from the LD light source device can be easily transmitted by the condensing optical system. Can be condensed.

Patent No. 5,157,961

However, in the LD light source device described above, the structure of the step-like mirror that constitutes the compression optical system is complicated, and therefore the work of producing the compression optical system and the work of incorporating the compression optical system into the device are complicated. There is a problem that it is difficult to reduce the size of the apparatus.
In addition, it is difficult to use light other than light that travels along the central axis of the light beam among the laser light emitted from the LD.

An object of the present invention is to two-dimensionally compress the distance between the central axes of the beam bundles of the laser beams emitted from each of the LDs in the light source unit, and to have a simple structure and reduce the size of the apparatus. It is an object to provide an LD light source device and a light source device including the LD light source device.
In addition to the above object, another object of the present invention is to provide an LD light source device having a high utilization rate of light emitted from an LD and a light source device including the LD light source device.

The LD light source device of the present invention has three directions orthogonal to each other as an x direction, a y direction, and a z direction.
A light source unit configured such that a plurality of LD arrays, each of which is arranged in a state where a plurality of LDs emitting laser beams in the z direction are arranged apart from each other in the x direction, are arranged apart from each other in the y direction;
A compression optical system that two-dimensionally compresses the distance between the central axes of the beam bundles of the laser beams emitted from each of the LDs in the light source unit;
The compression optical system comprises an integral prism,
The prism includes a light incident surface facing each light emitting surface of the LD;
A plurality of light reflecting surfaces, which are formed corresponding to each of the LD groups composed of the plurality of LDs arranged in the y direction, reflect each of the beam bundles of the laser light incident on the light incident surface in the x direction. A primary reflection mechanism;
A secondary reflection mechanism that compresses the distance between the central axes of the light beams of the laser beam reflected by the primary reflection mechanism in the y direction;
Each of the light reflection surfaces in the primary reflection mechanism includes a central axis of a light beam bundle of a laser beam reflected by the light reflection surface and a central axis of a light beam bundle of a laser beam reflected by an adjacent light reflection surface. The distance between them in the z direction is smaller than the distance between the centers of the light emitting surfaces of the LDs adjacent in the x direction.

In the LD light source device of the present invention, it is preferable that the light reflecting surfaces adjacent to each other in the primary reflecting mechanism are continuous via a plane parallel to the light incident surface.
Further, the secondary reflection mechanism includes a first light reflection surface that reflects in the y direction each of the beam bundles of the laser light reflected by the light reflection surface in the primary reflection mechanism, and the second light reflection surface is reflected by the first light reflection surface. It is preferable that the second light reflecting surface that reflects each of the beam bundles of the laser beam thus produced in the x direction is formed.
The light source unit includes a frame for fixing each of the LDs.
It is preferable that a reference surface extending along one plane is formed on one surface of the frame, and the prism is arranged so that the light incident surface faces the reference surface.
In addition, a collimating lens portion may be provided on the light incident surface of the prism corresponding to each of the LDs.

The light source device of the present invention includes the LD light source device described above,
And a condensing optical member for condensing the laser light from the LD light source device.

The light source device of the present invention may have a fluorescent member that emits fluorescence when the laser light from the LD light source device is irradiated through the condensing optical member.
Such a light source device preferably has a condensing mirror that condenses the fluorescence from the fluorescent member.

According to the present invention, the distance between the central axes of the beam bundles of the laser beams emitted from the LDs in the light source unit can be two-dimensionally compressed by the compression optical system. Moreover, since the compression optical system is composed of an integral prism, the apparatus can be downsized with a simple structure.
Further, according to the configuration in which the light reflecting surfaces adjacent to each other in the primary reflecting mechanism are continuous via a plane parallel to the light incident surface, the laser light emitted from the LD is along the central axis of the light beam. Since the light other than the traveling light is reflected by the plane between the adjacent light reflecting surfaces, a high light utilization rate can be obtained.

It is explanatory drawing which shows the structure in an example of LD light source device of this invention. It is AA sectional drawing of the LD light source device shown in FIG. It is explanatory drawing which shows the structure in an example of the fiber irradiation type light source device carrying the light source device of this invention. It is explanatory drawing which shows the compression optical system provided with the collimating lens part. It is explanatory drawing which shows the modification of a compression optical system. It is explanatory drawing which shows the other modification of a compression optical system. It is explanatory drawing which shows the structure in the other example of LD light source device of this invention.

Embodiments of the present invention will be described below.
FIG. 1 is a plan view showing a configuration in an example of an LD light source device of the present invention. 2 is a cross-sectional view of the LD light source device taken along the line AA in FIG. 1 and 2, the x direction, the y direction, and the z direction indicated by arrows are three directions orthogonal to each other.
This LD light source device 10 compresses two-dimensionally the distance between the central axes of a light bundle by a light source unit 11 having a plurality of LDs (laser diodes) 12 and laser light emitted from each of the LDs 12 in the light source unit 11. The compression optical system 20 formed of an integral prism and a frame-shaped fixing member 40 that fixes the compression optical system 20 are configured. In FIG. 2, illustration of the fixing member 40 is omitted for convenience.

In the light source unit 11, a plurality of (four in the illustrated example) LDs 12 that emit laser light in the z direction are arranged in a state of being spaced apart from each other in the x direction, whereby the x direction An LD array 13 extending in the direction is formed. A plurality (two in the illustrated example) of the LD rows 13 are arranged apart from each other in the y direction.
The light source unit 11 is provided with a rectangular plate-like frame 15 that fixes each of the LDs 12. Specifically, a plurality of through holes 16 are formed in the frame 15 according to a pattern corresponding to the arrangement pattern of the LDs 12, and the LD 12 is fixed in each through hole 16.
A collimating lens 17 is disposed in each through hole 16 of the frame 15 so as to face the light emitting surface of the LD 12. The collimating lens 17 is held by a holding member 18.
Also, a reference surface S extending along one plane is formed on one surface (the upper surface in FIG. 2) of the frame 15 and serves as a reference for arranging the prisms constituting the compression optical system 20. As a material constituting the frame 15, aluminum alloy such as ADC, cast iron such as FC, or the like can be used.

The prism constituting the compression optical system 20 has a light incident surface 21 on which the laser light from each of the LDs 12 is incident and a light emitting surface 22 on which the laser light is emitted.
The light incident surface 21 is formed to face each light emitting surface of the LD 12 along a plane perpendicular to the z direction (a plane extending in the x direction and the y direction). Specifically, the prism constituting the compression optical system 20 is disposed in a state where the light incident surface 21 faces the reference surface S formed by one surface of the frame 15 in parallel. The surface roughness Ra of the light incident surface 21 is preferably, for example, 50 nm or less.
The light emission surface 22 is formed by one end surface of the prism in the x direction, and is a plane perpendicular to the x direction.
Further, the light incident surface 21 and the light emitting surface 22 are preferably provided with a non-reflective coating.

  The prism constituting the compression optical system 20 includes a primary reflection mechanism 25 including a plurality of light reflection surfaces 26. Each of the light reflection surfaces 26 in the primary reflection mechanism 25 is formed in a state of being separated from each other in the x direction corresponding to each of the LD groups 14 including a plurality of LDs 12 arranged in the y direction. These light reflecting surfaces 26 reflect each of the beam bundles of the laser light incident on the light incident surface 21 from each of the LDs 12 in the LD group 14 in the x direction from the z direction. It is formed in an inclined state at an angle of 45 °. The surface roughness Ra of the light reflecting surface 26 is preferably, for example, 50 nm or less.

  Each of the light reflecting surfaces 26 in the primary reflecting mechanism 25 includes a central axis Lc of the light beam reflected by the laser light reflected by the light reflecting surface 26 and a light beam emitted by the laser light reflected by the adjacent light reflecting surface 26. The distance p2 in the z direction from the center axis Lc of the laser diode is formed to be smaller than the distance p1 between the centers of the light emitting surfaces of the LDs 12 adjacent in the x direction. With such a configuration, when each of the light bundles of the laser light emitted from each LD 12 in the z direction is reflected in the x direction by each light reflecting surface 26, each of the light bundles traveling in the x direction. The distance between the central axes is compressed in the z direction.

The ratio (p2 / p1) between the distance p2 between the central axes Lc of the light beams and the center distance p1 between the light emitting surfaces of the LDs 12 is, for example, 0.15 to 0.6.
As a specific example, the center-to-center distance p1 between the light emitting surfaces of the LDs 12 adjacent in the x direction is 11 mm, and the divergence angle of the emitted laser light is small (parallel to the junction surface of the stacked crystal of the LD element). When the respective LDs 12 are arranged so that the x direction becomes the x direction and the focal length of the collimating lens 17 is 4.7 mm, the central axis of the light beam by the laser light reflected by the adjacent light reflecting surface 26 The distance p2 in the z direction from Lc is 2 mm (p2 / p1 = 0.182).
On the other hand, the distance p1 between the centers of the light emitting surfaces of the LDs 12 adjacent to each other in the x direction is 11 mm, and the fast axis direction in which the emitted laser light has a large divergence angle (the direction perpendicular to the junction surface of the stacked crystal of the LD element) is the x direction. When the LDs 12 are arranged such that the distance p2 in the z direction between the laser beam reflected by the adjacent light reflecting surfaces 26 and the central axis Lc of the light beam is 5 mm (p2 / p1 = 0) 454).
In order to reduce the thickness in the z direction of the prism constituting the compression optical system 20, the former configuration, that is, the configuration in which each of the LDs 12 in the light source unit 11 is arranged so that the slow axis direction is the x direction is preferable. .

  Further, in the primary reflection mechanism 25, the light reflection surfaces 26 adjacent to each other are continuously formed via a plane 27 parallel to the light incident surface 21. More specifically, of the two side edges 26a and 26b extending in the y direction on the light reflecting surface 26, one side edge 26a spaced from the light incident surface 21 and two side edges on the adjacent light reflecting surface 26 26a and 26b, the other side edge 26b that is close to the light incident surface 21 has the same distance from the light incident surface 21. A plane 27 parallel to the light incident surface 21 is formed between one side edge 26 a of the light reflecting surface 26 and the other side edge 26 b of the adjacent light reflecting surface 26.

  In addition, the prism constituting the compression optical system 20 includes a secondary reflection mechanism 30 that compresses the distance between the central axes of the light beams reflected by the light reflecting surfaces 26 in the y direction. The secondary reflecting mechanism 30 includes a first light reflecting surface 31 that reflects in the y direction each of the beam bundles of the laser beams traveling in the x direction reflected by the light reflecting surface 26, and the first light reflecting surface 31 reflects the light beams. And a second light reflecting surface 35 that reflects each of the beam bundles of the laser beam traveling in the y direction in the x direction.

  In the secondary reflection mechanism 30 of this example, two first light reflection surfaces 31 and second light reflection surfaces 35 are formed corresponding to the two LD rows 13. More specifically, each of the first light reflecting surfaces 31 is symmetrical with respect to a plane perpendicular to the y direction (a plane extending in the x direction and the z direction) including the central position between the two LD rows 13. In such a manner, they are formed apart from each other while being inclined at an angle of 45 ° with respect to a plane perpendicular to the x direction (a plane extending in the y direction and the z direction). Each of the second light reflecting surfaces 35 is formed in a state of facing the first light reflecting surface 31 in parallel. In FIG. 1, H is a cavity. By adopting such a configuration, a part of the outer side of the light bundle by the laser beam traveling in the x direction emitted from the LD 12 of one LD array 13 and the LD 12 of the other LD array 13 are emitted. A part of the outer side of the light beam by the laser beam traveling in the x direction is reflected by each of the first light reflecting surfaces 31 so as to approach each other in the y direction, and is further reflected by each of the second light reflecting surfaces 35 in the x direction. Is reflected. As a result, the distance between the central axes of the light beams traveling in the x direction is substantially compressed in the y direction.

In the prism constituting the compression optical system 20, the light reflecting surface 26 is preferably formed using a sol-gel method. The sol-gel method is a method of obtaining a solid glass from a metal alkoxide solution through a sol state and a gel state. By using this method to form the light reflecting surface 26, the light reflecting surface 26 and the flat surface 27 are formed. The boundary edge (ridge line) between them can be formed sharply.
Hereinafter, an example of a method for manufacturing a prism using the sol-gel method will be described.
Mix silica (SiO ₂ ) particles (for example, nanometer size), TEOS (Si (OC ₂ H ₅ ) ₄ : tetraethoxysilane), ethanol, distilled water, and hydrochloric acid or ammonia water at respective concentrations. To prepare a dispersion (sol). The dispersion is poured into a mold having a predetermined shape, and TEOS is hydrolyzed and polymerized to form a wet gel. Then, the wet gel is gradually heated to form a porous wet gel that can be transported, and this is placed in a furnace and sintered at 1300 ° C. or higher to produce a transparent quartz glass prism. .

In the LD light source device 10 described above, laser light is emitted in the z direction from each LD 12 in the light source unit 11. Each of the laser beams is incident on the light incident surface 21 of the prism constituting the compression optical system 20 via the collimating lens 17.
In the prism constituting the compression optical system 20, each of the light beams by the laser light that is incident on the light incident surface 21 and travels in the z direction is reflected in the x direction by each of the light reflecting surfaces 26 in the primary reflection mechanism 25. . At this time, the distance between the central axes of the beam bundles of the laser light traveling in the x direction is compressed in the z direction.
Next, each of the beam bundles of the laser light traveling in the x direction is reflected in the y direction by each of the first light reflecting surfaces 31 in the secondary reflection mechanism 30. At this time, the beam bundle of the laser beam related to the LD 12 in one LD row 13 and the beam bundle of the laser beam related to the LD 12 in the other LD row 13 approach each other in the y direction by each of the first light reflecting surfaces 31. Reflected to do. Thereafter, each of the beam bundles of the laser light traveling in the y direction is reflected in the y direction by each of the second light reflecting surfaces 35. As a result, the distance between the central axes of the beam bundles of the laser beam traveling in the x direction is compressed in the y direction.
In this way, each of the beam bundles of the laser light traveling in the x direction, in which the distance between the central axes is two-dimensionally compressed, is emitted from the light emitting surface 22.

FIG. 3 is an explanatory diagram showing a configuration of an example of a fiber irradiation type light source device equipped with the light source device of the present invention. This light source device has a housing 50, and the LD light source device 10 having the configuration shown in FIG. A light reflecting member 51 that reflects the laser light L1 emitted from the LD light source device 10 in the x direction in the z direction is disposed in front of the emission surface of the compression optical system 20 in the LD light source device 10.
A condensing optical member 52 that condenses the laser light L <b> 1 from the light reflecting member 51 is disposed in the housing 50. The condensing optical member 52 is arranged such that its optical axis extends in the z direction. A fluorescent member 53 that emits fluorescence L2 when the laser light L1 from the LD light source device 10 is irradiated through the condensing optical member 52 is disposed at the focal point of the condensing optical member 52. A condensing mirror 55 made of an elliptical reflecting mirror that condenses the fluorescent light L2 from the fluorescent member 53 is disposed so as to be positioned at one focal point. The fluorescent member 53 is held by the heat transfer plate 54.
Further, in this light source device, an optical fiber 56 that receives and guides the fluorescent light L2 from the condensing mirror 55 is provided so as to extend from the inside of the housing 50 to the outside through the housing 50. . The optical fiber 56 is disposed so that the incident end face thereof is positioned at the other focal point of the condenser mirror 55, and is fixed by the fixing member 57 in this state.
The LD light source device 10 is fixed to a heat sink 58 that radiates heat generated in the light source unit 11. A cooling fan 59 for cooling the heat sink 58 is provided behind the heat sink 58.

  In this light source device, the laser light L1 emitted from the LD light source device 10 in the x direction is reflected by the light reflecting member 51 in the z direction. Then, the laser light L1 traveling in the z direction is condensed by the condensing optical member 52 and is incident on the fluorescent member 53, whereby the fluorescent member 53 emits the fluorescent light L2. The fluorescence L2 emitted from the fluorescent member 53 is collected by the condenser mirror 55 and is incident on the incident end face of the optical fiber 56. The fluorescence L2 incident on the incident end face of the optical fiber 56 is guided by the optical fiber 56 and emitted from the exit end face.

According to the LD light source device 10 of the present invention, the compression optical system 20 can two-dimensionally compress the distance between the central axes of the light beams by the laser light emitted from each of the LDs 12 in the light source unit 11. Moreover, since the compression optical system 20 is composed of an integral prism, the apparatus can be downsized with a simple structure.
In addition, the light reflecting surfaces 26 adjacent to each other in the primary reflecting mechanism 25 are continuous via a plane 27 parallel to the light incident surface 21, so that the central axis of the light beam out of the laser light emitted from the LD 12. Since light other than the light traveling along is reflected by the plane 27 between the adjacent light reflecting surfaces 26, a high light utilization rate is obtained.

  The LD light source device of the present invention is not limited to the above embodiment, and various modifications can be made as follows.

(1) As shown in FIG. 4, the light incident surface 21 of the prism constituting the compression optical system 20 is provided with a collimating lens portion 23 protruding from the light incident surface 21 corresponding to each LD 12. May be. The protruding height of the collimating lens part 23 from the light incident surface 21 is, for example, 2 mm.

(2) The specific configuration of the secondary reflection mechanism 30 is not limited to that shown in FIG. 1 as long as the distance between the central axes of the beam bundles of the laser beam traveling in the x direction is compressed in the y direction. . For example, as shown in FIG. 5, two first light reflecting surfaces 31 that are formed corresponding to each of the LD rows 13 and reflect each of the beam bundles of the laser beams traveling in the x direction in the same y direction. Even if the secondary reflection mechanism 30 is formed by the single second light reflecting surface 35 that reflects each of the beam bundles of the laser beams traveling in the y direction from the first light reflecting surfaces 31 in the x direction. Good.

  In addition, as shown in FIG. 6, a first light reflecting surface 31 that reflects only the light beam by the laser beam related to the LD 12 of one LD array 13 from the x direction to the y direction, and the first light reflecting surface 31 to the y direction The secondary reflecting mechanism 30 may be formed by the single second light reflecting surface 35 that reflects each of the light beams by the laser light traveling to the x direction in the x direction.

(3) In the LD light source device 10 shown in FIG. 1, the two LD rows 13 are provided. However, the number of LD rows 13 is not limited to two. For example, as shown in FIG. LD arrays may be provided.

10 LD light source device 11 Light source unit 12 LD
13 LD array 14 LD group 15 Frame 16 Through-hole 17 Collimating lens 18 Holding member 20 Compression optical system 21 Light incident surface 22 Light emitting surface 23 Collimating lens unit 25 Primary reflection mechanism 26 Light reflecting surfaces 26a and 26b Side edge 27 Plane 30 Second Next reflecting mechanism 31 First light reflecting surface 35 Second light reflecting surface 40 Fixing member 50 Housing 51 Light reflecting member 52 Condensing optical member 53 Fluorescent member 54 Heat transfer plate 55 Condensing mirror 56 Optical fiber 57 Fixing member 58 Heat sink 59 Cooling fan H Cavity Lc Center axis L1 of light beam Laser light L2 Fluorescence S Reference plane

Claims (8)

When three directions orthogonal to each other are defined as an x direction, a y direction, and a z direction,
A light source unit configured such that a plurality of LD arrays, each of which is arranged in a state where a plurality of LDs emitting laser beams in the z direction are arranged apart from each other in the x direction, are arranged apart from each other in the y direction;
A compression optical system that two-dimensionally compresses the distance between the central axes of the beam bundles of the laser beams emitted from each of the LDs in the light source unit;
The compression optical system comprises an integral prism,
The prism includes a light incident surface facing each light emitting surface of the LD;
A plurality of light reflecting surfaces, which are formed corresponding to each of the LD groups composed of the plurality of LDs arranged in the y direction, reflect each of the beam bundles of the laser light incident on the light incident surface in the x direction. A primary reflection mechanism;
A secondary reflection mechanism that compresses the distance between the central axes of the light beams of the laser beam reflected by the primary reflection mechanism in the y direction;
Each of the light reflection surfaces in the primary reflection mechanism includes a central axis of a light beam bundle of a laser beam reflected by the light reflection surface and a central axis of a light beam bundle of a laser beam reflected by an adjacent light reflection surface. An LD light source device, wherein the distance in the z direction is smaller than the distance between the centers of the light emitting surfaces of the LDs adjacent in the x direction.   2. The LD light source device according to claim 1, wherein the light reflecting surfaces adjacent to each other in the primary reflecting mechanism are continuous via a plane parallel to the light incident surface.   The secondary reflection mechanism is reflected by the first light reflection surface, the first light reflection surface reflecting in the y direction each of the light beams by the laser light reflected by the light reflection surface in the primary reflection mechanism, and the second light reflection surface 3. The LD light source device according to claim 1, wherein the LD light source device is configured by a second light reflecting surface that reflects each of the beam bundles of the laser light in the x direction. The light source unit includes a frame for fixing each of the LDs.
A reference surface extending along one plane is formed on one surface of the frame, and the prism is arranged so that the light incident surface faces the reference surface. The LD light source device according to claim 3.   The LD light source device according to any one of claims 1 to 4, wherein a collimating lens portion is provided on the light incident surface of the prism corresponding to each of the LDs. The LD light source device according to any one of claims 1 to 5,
A light source device comprising: a condensing optical member that condenses laser light from the LD light source device.   The light source device according to claim 6, further comprising a fluorescent member that emits fluorescence when the laser light from the LD light source device is irradiated through the condensing optical member.   The light source device according to claim 7, further comprising a condensing mirror that condenses the fluorescence from the fluorescent member.

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