WO2021208996A1

WO2021208996A1 - Laser light source

Info

Publication number: WO2021208996A1
Application number: PCT/CN2021/087441
Authority: WO
Inventors: 陈彬
Original assignee: 深圳市绎立锐光科技开发有限公司
Priority date: 2020-04-17
Filing date: 2021-04-15
Publication date: 2021-10-21
Also published as: CN113534586A

Abstract

Disclosed is a laser light source, comprising a laser array, a convergence optical element, a first light shaping element, and a second light shaping element, which are arranged in sequence, wherein the laser array is used to generate a laser beam array; the convergence optical element is used to converge the laser beam array; the first light shaping element is used to enable the laser beam array emitted by the convergence optical element to be converged in the slow-axis direction so as to reduce the spot length of the laser beam array at the convergence point in the slow-axis direction; and the second light shaping element is used to enable the divergence angle of the laser beam array emitted by the first light shaping element to be compressed in the fast-axis direction and extend the spot length of the laser beam array at the convergence point in the fast-axis direction. According to the present invention, the spot length of a light spot formed by the laser beam array at the convergence point in the slow-axis direction is reduced, and the spot length in the fast-axis direction is extended, thereby reducing the requirement for the core diameter of a light guide element and thus also reducing the cost of the light guide element.

Description

A laser light source

Technical field

The present invention relates to the field of laser technology, in particular to a laser light source.

Background technique

As a new type of light source with high brightness and high collimation, laser light source is gradually being applied to the fields of projection and lighting. However, as the requirements for projection and illumination are getting higher and higher, the requirements for the power and quality of the laser light source are also getting higher and higher.

The inventors of the present application have discovered during long-term research and development that, as shown in FIG. 1, the laser beam array generated by the current laser element 110 is collimated by the collimating lens 120 and then directly converged by the converging lens 130 and then emitted to the light guide element 140, such as As shown in FIG. 2, since the divergence angle of the collimated laser beam array in the slow axis direction is greater than the divergence angle in the fast axis direction, the length of the light spot formed on the light guide element 140 in the slow axis direction after convergence Is greater than the length in the fast axis direction; as shown in Figure 3, and since the collimated laser beam array has a larger aperture in the fast axis direction than the aperture on the slow axis, it is formed on the light guide element 140 after being converged The divergence angle of the light spot in the fast axis direction is greater than the divergence angle in the slow axis direction. Since the core diameter and NA (Numerical Aperture) of the light guide element 140 are uniform, the core diameter of the light guide element 140 needs to be larger than the aperture of the light spot in the slow axis direction, and the NA of the light guide element 140 needs to be larger than the light spot. The divergence angle in the fast axis direction. Therefore, as the core diameter of the light guide element 140 increases, its cost will also increase, and there will be a problem that it is not easy to bend.

Summary of the invention

The present invention provides a laser light source to solve the technical problem of higher requirements on the core diameter of the optical fiber in order to increase the laser power in the prior art.

In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a laser light source, including:

The laser array includes a plurality of laser elements arranged in a two-dimensional array, and the fast axis direction and the slow axis direction of the plurality of laser elements are the same, and are used to generate a collimated laser beam array;

A converging optical element, which is arranged on the light-emitting side of the laser array, and is used to converge the laser beam array;

The first light shaping element is arranged on the light exit side of the converging optical element, and is used for converging the laser beam array emitted by the converging optical element in the slow axis direction, so as to reduce the laser beam array at the converging point along the slow axis The length of the spot in the direction;

The second light-shaping element is arranged on the light-emitting side of the first light-shaping element, and is used to compress the divergence angle of the laser beam array emitted by the first light-shaping element in the fast axis direction and expand the laser beam array in the fast axis direction. The length of the spot along the fast axis of the convergence point.

In a specific embodiment, the first light shaping element is also used to expand the divergence angle of each laser beam in the laser beam array emitted by the converging optical element in the slow axis direction.

In a specific embodiment, the first light shaping element is a cylindrical lens array, the cylindrical lens array includes a plurality of cylindrical lenses, and each cylindrical lens extends along the fast axis direction for receiving corresponding The laser beams produced by a row of lasers arranged in the direction of the fast axis.

In a specific embodiment, the second light shaping element is a concave cylindrical lens, and the length direction of the concave cylindrical lens is parallel to the slow axis direction.

In a specific embodiment, the laser light source further includes a third light-shaping element, and the third light-shaping element is disposed between the laser array and the converging optical element, and is used to compress the laser beam along the slow axis direction. The divergence angle of the laser beam produced by each row of lasers arranged in the fast axis direction.

In a specific embodiment, the third light shaping element is a cylindrical lens array, and the cylindrical lens array includes a plurality of cylindrical lenses, and each cylindrical lens extends along the fast axis direction for receiving corresponding The laser beams produced by a row of lasers arranged in the direction of the fast axis.

In a specific embodiment, the laser light source further includes a fourth light-shaping element, and the fourth light-shaping element is disposed between the converging optical element and the fourth light-shaping element, and is configured to move in the slow axis The divergence angle of the laser beam generated by each row of lasers arranged along the fast axis direction is compressed in the direction.

In a specific embodiment, the fourth light-shaping element is a cylindrical lens array, the cylindrical lens array includes a plurality of cylindrical lenses, and each cylindrical lens extends in the fast axis direction for receiving corresponding The laser beams produced by a row of lasers arranged in the direction of the fast axis.

In a specific embodiment, the geometric centers of the plurality of cylindrical lenses are located on the same curve, and the convex surface of the curve faces the converging optical element.

In a specific embodiment, the laser light source further includes a light guide element, the light guide element is arranged on the light exit side of the second light shaping element, and is used for emitting the laser beam array to the second light shaping element Conduct orientation.

In a specific embodiment, the laser array further includes a plurality of collimating lenses corresponding to the laser elements on a one-to-one basis, and the collimating lenses are used for performing the laser beam array emitted by the plurality of laser elements. Collimation adjustment.

In the present invention, a converging optical element, a first light-shaping element and a second light-shaping element are arranged on the laser light source, and the laser beam array generated by the laser array is converged and twice light-shaped, so that the laser beam array emitted to the light guide element can be The spot length of the spot formed by the converging point along the slow axis direction is reduced, and the spot length of the spot formed by the laser beam array at the converging point along the fast axis direction is enlarged, which can reduce the requirement on the core diameter of the light guide element, thereby reducing the light guide The cost of components.

Description of the drawings

In order to explain the technical solutions in the embodiments of the present invention more clearly, the following will briefly introduce the drawings needed in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative work, other drawings can be obtained based on these drawings, among which:

Fig. 1 is a schematic diagram of the structure of a laser light source in the prior art;

2 is a schematic diagram of a light spot formed on a light guide element by a laser light source in the prior art;

3 is a schematic diagram of the angular distribution of the light spot formed by the laser light source on the light guide element in the prior art;

4 is a schematic structural diagram of an embodiment of the laser light source of the present invention along the slow axis direction;

FIG. 5 is a schematic structural diagram of an embodiment of the laser light source of the present invention along the fast axis direction;

6 is a schematic diagram of a three-dimensional structure of a laser element in an embodiment of the laser light source of the present invention;

7 is a schematic diagram of the structure of the laser element and the collimating lens along the slow axis direction in an embodiment of the laser light source of the present invention;

8 is a schematic diagram of the structure of the laser element and the collimating lens along the fast axis direction in an embodiment of the laser light source of the present invention;

9 is a schematic diagram of the convergent optical element and the first light-shaping element in another specific embodiment of the laser light source of the present invention along the slow axis direction;

10 is a schematic diagram of a spot formed at a converging point of a laser beam array emitted from a first light-shaping element in an embodiment of the laser light source of the present invention;

11 is a schematic diagram of the angular distribution of the light spot formed at the converging point of the laser beam array emitted from the first light-shaping element in an embodiment of the laser light source of the present invention;

12 is a schematic diagram of the spot formed at the converging point of the laser beam array emitted from the second light-shaping element in an embodiment of the laser light source of the present invention;

13 is a schematic diagram of the angular distribution of the light spot formed at the converging point of the laser beam array emitted from the second light-shaping element in an embodiment of the laser light source of the present invention;

14 is a schematic diagram of another embodiment of the laser light source of the present invention along the direction of the slow axis;

15 is a schematic structural diagram along the fast axis direction of another embodiment of the laser light source of the present invention;

16 is a schematic view of another embodiment of the laser light source of the present invention along the direction of the slow axis;

FIG. 17 is a schematic structural diagram along the fast axis direction of another embodiment of the laser light source of the present invention;

18 is a schematic diagram of another embodiment of the laser light source of the present invention along the direction of the slow axis;

19 is a schematic diagram of another embodiment of the laser light source of the present invention along the fast axis direction.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

The terms "first" and "second" in this application are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. In the description of this application, "plurality" means at least two, such as two, three, etc., unless specifically defined otherwise. In addition, the terms "including" and "having" and any variations of them are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes unlisted steps or units, or optionally also includes Other steps or units inherent to these processes, methods, products or equipment. The term "and/or" is only an association relationship that describes the associated objects, indicating that there can be three relationships, for example, A and/or B, which can mean: A alone exists, A and B exist at the same time, and B exists alone. These three situations. In addition, the character "/" in this text generally indicates that the associated objects before and after are in an "or" relationship.

4 and 5, the laser light source embodiment of the present invention includes a laser array 200, a converging optical element 300, a first light shaping element 400, and a second light shaping element 500. The laser array 200 includes a plurality of two-dimensional arrays. The laser element 210, where the fast axis direction and the slow axis direction of the multiple laser elements 210 are the same, are used to generate the laser beam array 610; the converging optical element 300 is arranged on the light exit side of the laser array 200 and is used to converge the laser beam array 610; The first light shaping element 400 is arranged on the light exit side of the converging optical element 300, and is used to converge the laser beam array 610 emitted by the converging optical element 300 in the slow axis direction, so as to reduce the laser beam array 610 at the converging point along the slow axis direction. The second light-shaping element 500 is arranged on the light-emitting side of the first light-shaping element 400, and is used to compress the divergence angle of the laser beam array 620 emitted by the first light-shaping element 400 in the fast axis direction and expand the laser The spot length of the light beam array 620 along the fast axis direction at the converging point.

In the embodiment of the present invention, the converging optical element 300, the first light shaping element 400, and the second light shaping element 500 are arranged in the laser light source, and the laser beam array 610 generated by the laser array 200 is converged and light-shaped twice, so that the laser beam can be emitted to The laser beam array 630 of the light guide element has a reduced spot length along the slow axis of the spot formed at the converging point, and the laser beam array 630 has an enlarged spot length along the fast axis direction at the converging point, thereby reducing the impact on the light guide element. The requirements of the core diameter, thereby reducing the cost of the light guide element.

In this embodiment, the first light shaping element 400 is also used to expand the divergence angle of each laser beam in the laser beam array 610 emitted by the condensing optical element 300 in the slow axis direction.

In this embodiment, the laser light source further includes a light guide element 700, which is disposed on the light exit side of the second light shaping element 500, and is used to guide the laser beam array 630.

In this embodiment, the ratio of the divergence angle of each laser beam in the fast axis direction to the divergence angle in the slow axis direction in the laser beam array 630 emitted to the light guide element 700 is greater than or equal to 0.8, such as 0.8, 0.9, or 1.

In this embodiment, the laser light source may further include a wavelength conversion device (not shown in the figure), and the wavelength conversion device is disposed on the light exit side of the light guide element 700 for performing wavelength conversion on the laser beam array 630.

In this embodiment, the light guide element 700 takes an optical fiber as an example for description. In other embodiments, the light guide element 700 may also be an integrator rod or the like.

In this embodiment, the laser array 200 further includes a plurality of collimating lenses 220 corresponding to the laser elements 210 in a one-to-one manner, and the collimating lenses 220 are used to adjust the collimation of the laser beam array 610.

6 together, in this embodiment, the laser element 210 is a strip-shaped light-emitting chip, such as a semiconductor laser chip. The laser element 210 is provided with a light-emitting surface 211, the light-emitting surface 211 is disposed facing the converging optical element 300, the length of the light-emitting surface 211 is d1, and the width of the light-emitting surface 211 is d2. In this application, the length direction of the light-emitting surface 211 is defined as the slow axis direction of the laser element 210, that is, the a-axis direction in the figure; the width direction of the light-emitting surface 211 is defined as the fast axis direction of the laser element 210, that is, the b-axis direction in the figure. ; The light-emitting direction of the laser element 210, that is, the c-axis direction in the figure is perpendicular to the light-emitting surface 211 of the laser element 210.

In this embodiment, the length d1 of the light-emitting surface 211 may be greater than or equal to 10 μm, such as 10 μm, 12 μm, or 13 μm, and the divergence angle of the light-emitting surface 211 along the slow axis direction of the laser element 210 may be 12° to 16°, such as 12. °, 14° or 16°. The width d2 of the light-emitting surface 211 may be less than or equal to 5 μm, such as 5 μm, 4 μm, or 2 μm, and the divergence angle of the light-emitting surface 211 along the fast axis direction of the laser element 210 may be 43° to 47°, such as 43°, 45°, or 47°. °. Since the divergence angle of the light-emitting surface 211 along the fast axis direction of the laser element 210 is relatively large relative to the divergence angle along the slow axis direction of the laser element 210, the plurality of laser elements 210 are generally set to have a greater distance along the fast axis direction than along the slow axis. The distance between directions.

Referring to FIGS. 7 and 8 together, in this embodiment, the collimating lens 220 may be a biconvex lens. The focal length of the collimating lens 220 is f1, and the divergence half angle θ of the collimated laser beam array 610 along the slow axis direction of the light emitting element 110, where tanθ=d/f1.

In other embodiments, the collimating lens 220 may also be a plano-convex lens, which is not limited here.

In this embodiment, the converging optical element 300 may be a converging lens, such as a biconvex lens. The focal length of the converging optical element 300 is f2, and the length of the spot formed at the converging point of the convergent laser beam array 610 along the slow axis direction is L, where L=d*f2/f1.

In this embodiment, the first light shaping element 400 is a column of cylindrical lens array arranged along the slow axis direction. The cylindrical lens array includes a plurality of cylindrical lenses, and each cylindrical lens extends in the fast axis direction for receiving The corresponding laser beams 610 generated by a row of lasers arranged along the fast axis direction.

In this embodiment, the cylindrical lens may be a plano-convex cylindrical lens, the plane of the plano-convex cylindrical lens is disposed facing the converging optical element 300, and the convex surface of the plano-convex cylindrical lens is disposed away from the converging optical element 300. In other embodiments, the cylindrical lens may also be a biconvex cylindrical lens.

Referring to FIG. 9, in other embodiments, the geometric center of the first light-shaping element 400 may also be located on the same curve, and the convex surface of the curve faces the converging optical element 300, so that each laser beam 610 can be incident on the first light beam. The light-shaping element 400 can thereby enable each first light-shaping element 400 to achieve a better light-shaping effect. Compared with the first light shaping elements 400 arranged in a straight line, the laser beam passing through the cylindrical lens in the edge area and the laser beam passing through the cylindrical lens in the middle area can achieve a better convergence effect.

4, 5, 10, and 11, since the length direction of the first light shaping element 400 is parallel to the fast axis direction, the first light shaping element 400 only acts on the laser beam array 610 in the slow axis direction. The convergence effect can make the laser beam array 620 emitted from the first light-shaping element 400 form a spot along the slow axis at the converging point, and the total length along the slow axis direction is smaller than that of the laser beam array 610 emitted from the converging optical element 300 at the converging point. The total length in the direction of the slow axis helps to reduce the requirement on the core diameter of the optical fiber, thereby reducing the cost of the optical fiber.

According to the principle of conservation of optical expansion: the cross-sectional area of the beam is compressed, and its divergence angle will inevitably increase. Therefore, the divergence angle of the spot formed by each laser beam 620 at the convergence point along the slow axis direction can be greater than the divergence angle of the spot formed by each laser beam 610 at the convergence point along the slow axis direction. At the same time, since the total beam angle of the laser beam array 620 is the same as that of the laser beam array 610, the space angle of the spots formed by the multiple laser beam arrays 620 at the converging point is reduced in the space angle along the slow axis direction, so that the laser beam array The light spot formed by the 620 at the convergence point is more uniform.

12 and 13 together, in this embodiment, the second light shaping element 500 may be a concave cylindrical lens, the length of the concave cylindrical lens is parallel to the slow axis direction, and is used to receive the laser beam array 620.

In this embodiment, the concave cylindrical lens may be a crescent-shaped cylindrical lens, and the concave surface of the crescent-shaped cylindrical lens faces away from the first light shaping element 400. The length direction of the second light shaping element 500 is parallel to the slow axis direction, and the angular distribution of the laser beam array 620 is adjusted and controlled only along the fast axis direction, so that the spot formed by the laser beam array 630 at the converging point is along the fast axis direction The total length of the laser beam array 620 at the convergence point is greater than the total length along the fast axis direction, and the divergence angle of each laser beam array 630 at the convergence point along the fast axis direction is smaller than that of each laser beam The divergence angle of the light spot formed by the array 620 at the convergence point along the fast axis direction. As a result, the difference between the divergence angle along the fast axis direction and the divergence angle along the slow axis direction of the spot formed by the laser beam array 630 emitted to the optical fiber at the convergence point is smaller than the angle threshold, and the divergence angle values are both small, and make The difference between the length along the slow axis direction and the length along the fast axis direction of the spot formed by the laser beam array 630 at the converging point is less than the length threshold, and the lengths are both small, which is further conducive to reducing the requirements on the core diameter and NA of the optical fiber. In turn, the cost and difficulty of setting up the optical fiber are reduced.

In other embodiments, the concave cylindrical lens can also be a plano-concave cylindrical lens, which is not limited here.

14 and 15, in another specific embodiment, the laser light source may further include a third light-shaping element 800, the third light-shaping element 800 is arranged between the laser array 200 and the converging optical element 300 for slow The divergence angle of the laser beam generated by each row of lasers 210 arranged along the fast axis direction is compressed in the axial direction. By providing the third light-shaping element 800, it is possible to prevent the collimated laser beam from having an excessively large divergence angle, resulting in that when the convergent optical element 300 is emitted to the corresponding first light-shaping element 400, it diverges and emits to the corresponding first light The first light-shaping element 400 adjacent to the shaping element 400 causes mutual interference, resulting in uneven light spots emitted.

In this embodiment, the third light shaping element 800 is a cylindrical lens array. The cylindrical lens array includes a plurality of cylindrical lenses. Each cylindrical lens extends in the fast axis direction and is used for receiving corresponding arrays in the fast axis direction. A row of lasers 210 generate laser beams.

16 and 17, in another specific embodiment, the laser light source may further include a fourth light-shaping element 900, the fourth light-shaping element 900 is arranged between the converging optical element 300 and the first light-shaping element 400, The divergence angle of the laser beam generated by each row of lasers 210 arranged along the fast axis direction is compressed in the slow axis direction. By providing the fourth light-shaping element 900, it is possible to prevent the collimated laser beam from having an excessively large divergence angle, resulting in that when the convergent optical element 300 is emitted to the corresponding first light-shaping element 400, it diverges and emits to the corresponding first light The first light-shaping element 400 adjacent to the shaping element 400 causes mutual interference, resulting in uneven light spots emitted.

In this embodiment, the fourth light shaping element 900 is a cylindrical lens array. The cylindrical lens array includes a plurality of cylindrical lenses. Each cylindrical lens extends in the fast axis direction and is used to receive corresponding arrays in the fast axis direction. A row of lasers 210 generate laser beams.

In this embodiment, the cylindrical lens may be a plano-convex cylindrical lens, the plane of the plano-convex cylindrical lens is arranged opposite to the converging optical element 300, and the convex surface of the plano-convex cylindrical lens is arranged to face the converging optical element 300. In other embodiments, the cylindrical lens may also be a biconvex cylindrical lens.

In this embodiment, the focal point of the fourth light-shaping element 900 can be located between the fourth light-shaping element 900 and the first light-shaping element 400, or can be located at the exit end of the first light-shaping element 400, that is, the first light-shaping element 400. The element 400 is located at the non-focus position of the fourth light-shaping element 900.

Referring to FIGS. 18 and 19, in another specific embodiment, the laser light source may also include a third light-shaping element 800 and a fourth light-shaping element 900 at the same time, wherein the third light-shaping element 800 and the fourth light-shaping element 900 For the structure and position of, refer to the above-mentioned laser light source embodiment, which will not be repeated here. By arranging the third light shaping element 800 and the fourth light shaping element 900 at the same time, the divergence angle of the laser beam can be better controlled, and the mutual interference can be further reduced.

The above are only the embodiments of the present invention, and do not limit the scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied to other related technologies In the same way, all fields are included in the scope of patent protection of the present invention.

Claims

A laser light source, characterized in that it comprises:

The laser array includes a plurality of laser elements arranged in a two-dimensional array, the fast axis direction and the slow axis direction of the plurality of laser elements are the same, and the laser beam array is generated;

A converging optical element, which is arranged on the light-emitting side of the laser array, and is used to converge the laser beam array;

The first light shaping element is arranged on the light exit side of the converging optical element, and is used for converging the laser beam array emitted by the converging optical element in the slow axis direction, so as to reduce the laser beam array at the converging point along the slow axis The length of the spot in the direction;

The second light-shaping element is arranged on the light-emitting side of the first light-shaping element, and is used to compress the divergence angle of the laser beam array emitted by the first light-shaping element in the fast axis direction and expand the laser beam array in the fast axis direction. The length of the spot along the fast axis of the convergence point.
The laser light source according to claim 1, wherein the first light shaping element is further used to expand the divergence angle of each laser beam in the laser beam array emitted by the converging optical element in the slow axis direction.
The laser light source according to claim 1, wherein the first light shaping element is a cylindrical lens array, and the cylindrical lens array includes a plurality of cylindrical lenses, and each cylindrical lens is along a fast axis. The direction extension is used to receive the corresponding laser beams generated by a row of lasers arranged along the fast axis direction.
The laser light source according to claim 1, wherein the second light shaping element is a concave cylindrical lens, and the length direction of the concave cylindrical lens is parallel to the slow axis direction.
The laser light source according to claim 1, wherein the laser light source further comprises a third light shaping element, and the third light shaping element is disposed between the laser array and the converging optical element for The divergence angle of the laser beam generated by each row of lasers arranged along the fast axis is compressed in the slow axis direction.
The laser light source according to claim 5, wherein the third light-shaping element is a cylindrical lens array, and the cylindrical lens array includes a plurality of cylindrical lenses, and each cylindrical lens is along a fast axis. The direction extension is used to receive the corresponding laser beams generated by a row of lasers arranged along the fast axis direction.
The laser light source according to claim 1 or 5, wherein the laser light source further comprises a fourth light-shaping element, and the fourth light-shaping element is disposed on the converging optical element and the first light-shaping element In between, it is used to compress the divergence angle of the laser beam generated by each row of lasers arranged along the fast axis in the slow axis direction.
7. The laser light source according to claim 7, wherein the fourth light shaping element is a cylindrical lens array, and the cylindrical lens array includes a plurality of cylindrical lenses, and each cylindrical lens is along a fast axis. The direction extension is used to receive the corresponding laser beams generated by a row of lasers arranged along the fast axis direction.
The laser light source according to claim 3, wherein the geometric centers of the plurality of cylindrical lenses are located on the same curve, and the convex surface of the curve faces the converging optical element.
The laser light source according to claim 1, wherein the laser light source further comprises a light guide element, the light guide element is arranged on the light exit side of the second light shaping element, and is used for treating the second light shaping element The emitted laser beam array is guided.
The laser light source according to claim 1, wherein the laser array further comprises a plurality of collimating lenses corresponding to the laser elements one-to-one, and the collimating lenses are used to emit light to the plurality of laser elements. The laser beam array is adjusted for collimation.