A laser light source

Abstract

The present invention discloses a laser light source, comprising a laser array, a converging optical element, a first light shaping element, and a second light shaping element arranged in sequence. The laser array is used to generate a laser beam array; the converging optical element is used to converge the laser beam array; the first light shaping element is used to converge the laser beam array emitted by the converging optical element in the slow axis direction, thereby reducing the spot length of the laser beam array at the convergence point along the slow axis direction; and the second light shaping element 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 spot length of the laser beam array at the convergence point along the fast axis direction. The present invention can reduce the spot length of the laser beam array formed at the convergence point along the slow axis direction and expand the spot length along the fast axis direction, thereby reducing the core diameter requirement of the optical waveguide element and thereby reducing the cost of the optical waveguide element.

Description

Technical Field

[0001] The present invention relates to the field of laser technology, and in particular to a laser light source. Background Art

[0002] Laser light sources, as a new type of high-brightness, high-collimation light source, are gradually being applied to fields such as projection and lighting. However, as the requirements for projection and lighting become increasingly sophisticated, the requirements for the power and quality of laser light sources are also becoming higher and higher.

[0003] The inventors of this application have found in their long-term research and development that Figure 1 As shown, 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, as shown in FIG. Figure 2 As shown in FIG, 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 optical element 140 after convergence in the slow axis direction is greater than the length in the fast axis direction; as shown in FIG. Figure 3 As shown, since the aperture of the collimated laser beam array in the fast axis direction is larger than that in the slow axis direction, the divergence angle of the light spot formed on the light guide element 140 after convergence in the fast axis direction is larger than that in the slow axis direction. However, 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 must be larger than the aperture of the light spot in the slow axis direction, and the NA of the light guide element 140 must be larger than the divergence angle of the light spot in the fast axis direction. Therefore, as the core diameter of the light guide element 140 increases, its cost also increases, and it may be difficult to bend. Summary of the Invention

[0004] The present invention provides a laser light source to solve the technical problem in the prior art that higher requirements are placed on the core diameter of an optical fiber in order to increase laser power.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a laser light source, comprising:

[0006] A laser array comprising a plurality of laser elements arranged in a two-dimensional array, wherein the fast axis direction and the slow axis direction of the plurality of laser elements are the same, and is used to generate a collimated laser beam array;

[0007] A converging optical element, disposed on the light-emitting side of the laser array, for converging the laser beam array;

[0008] a first light shaping element, disposed on the light-emitting side of the converging optical element, for converging the laser beam array emitted by the converging optical element in the slow axis direction, so as to reduce the spot length of the laser beam array at the convergence point along the slow axis direction;

[0009] The second light shaping element is disposed 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 to expand the spot length of the laser beam array at the convergence point along the fast axis direction.

[0010] In a specific embodiment, the first light shaping element is further configured 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.

[0011] In a specific embodiment, the first light shaping element is a cylindrical lens array, which includes a plurality of cylindrical lenses. Each cylindrical lens extends along the fast axis and is configured to receive a laser beam generated by a corresponding row of lasers arranged along the fast axis.

[0012] 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.

[0013] In a specific embodiment, the laser light source further includes a third light shaping element, which is disposed between the laser array and the converging optical element and is configured to compress, in the slow axis direction, the divergence angle of the laser beam generated by each row of lasers arranged along the fast axis direction.

[0014] In a specific embodiment, the third light shaping element is a cylindrical lens array, which includes a plurality of cylindrical lenses. Each cylindrical lens extends along the fast axis and is configured to receive a laser beam generated by a corresponding row of lasers arranged along the fast axis.

[0015] In a specific embodiment, the laser light source further includes a fourth light shaping element, which is disposed between the converging optical element and the fourth light shaping element and is configured to compress, in a slow axis direction, the divergence angle of the laser beam generated by each row of lasers arranged along the fast axis.

[0016] In a specific embodiment, the fourth light shaping element is a cylindrical lens array, which includes a plurality of cylindrical lenses. Each cylindrical lens extends along the fast axis and is configured to receive a laser beam generated by a corresponding row of lasers arranged along the fast axis.

[0017] 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.

[0018] In a specific embodiment, the laser light source further includes a light guide element, which is disposed on the light-emitting side of the second light shaping element and is used to guide the laser beam array emitted by the second light shaping element.

[0019] In a specific embodiment, the laser array further includes a plurality of collimating lenses corresponding one-to-one to the laser elements, and the collimating lenses are used to collimate and adjust the laser beam array emitted by the plurality of laser elements.

[0020] The present invention provides a converging optical element, a first light shaping element, and a second light shaping element in a laser light source to converge and twice shape the laser beam array generated by the laser array. This can reduce the length of the light spot formed at the convergence point of the laser beam array emitted to the optical waveguide element along the slow axis, and increase the length of the light spot formed at the convergence point along the fast axis, thereby reducing the requirements for the core diameter of the optical waveguide element and further reducing the cost of the optical waveguide element. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0022] Figure 1 It is a schematic diagram of the structure of a laser light source in the prior art;

[0023] Figure 2 Schematic diagram of a light spot formed by a laser light source on a light guide element in the prior art;

[0024] Figure 3 This 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;

[0025] Figure 4 This is a schematic structural diagram of an embodiment of a laser light source according to the present invention along the slow axis direction;

[0026] Figure 5 This is a schematic structural diagram of an embodiment of a laser light source according to the present invention along the fast axis direction;

[0027] Figure 6 1 is a schematic diagram of the three-dimensional structure of a laser element in one embodiment of a laser light source of the present invention;

[0028] Figure 7 1 is a schematic structural diagram of a laser element and a collimating lens along the slow axis direction in an embodiment of a laser light source of the present invention;

[0029] Figure 8 1 is a schematic structural diagram of a laser element and a collimating lens along the fast axis direction in an embodiment of a laser light source of the present invention;

[0030] Figure 9 2 is a schematic structural diagram of a converging optical element and a first light shaping element along the slow axis direction in another specific embodiment of the laser light source of the present invention;

[0031] Figure 10 Schematic diagram of a light spot formed at a convergence point by an array of laser beams emitted from a first light shaping element in one embodiment of a laser light source of the present invention;

[0032] Figure 11 2. FIG. 1 is a schematic diagram of the angular distribution of the light spots formed at the convergence point by the array of laser beams emitted from the first light shaping element in one embodiment of the laser light source of the present invention;

[0033] Figure 12 Schematic diagram of a light spot formed at a convergence point by an array of laser beams emitted from a second light shaping element in one embodiment of a laser light source of the present invention;

[0034] Figure 13 2. FIG. 1 is a schematic diagram of the angular distribution of the light spots formed at the convergence point by the array of laser beams emitted from the second light shaping element in one embodiment of the laser light source of the present invention;

[0035] Figure 14 This is a schematic structural diagram of another embodiment of the laser light source of the present invention along the slow axis direction;

[0036] Figure 15 1 is a schematic structural diagram of another embodiment of the laser light source of the present invention along the fast axis direction;

[0037] Figure 16 This is a schematic structural diagram of another embodiment of the laser light source of the present invention along the slow axis direction;

[0038] Figure 17 1 is a schematic structural diagram of another embodiment of the laser light source of the present invention along the fast axis direction;

[0039] Figure 18 This is a schematic structural diagram of another embodiment of the laser light source of the present invention along the slow axis direction;

[0040] Figure 19 It is a schematic structural diagram of another embodiment of the laser light source of the present invention along the fast axis direction. DETAILED DESCRIPTION

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0042] The terms "first" and "second" in this application are only used for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically limited. In addition, the terms "including" and "having" and any of their variations 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 also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices. The term "and / or" is merely an association relationship that describes associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0043] See also Figure 4 and Figure 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 laser elements 210 arranged in a two-dimensional array. The fast axis direction and the slow axis direction of the plurality of laser elements 210 are the same, and are used to generate a laser beam array 610. The converging optical element 300 is arranged on the light-emitting side of the laser array 200 and is used to converge the laser beam array 610. The first light shaping element 400 The second light shaping element 500 is disposed on the light-exiting side of the converging optical element 300 and is used to converge the laser beam array 610 emitted from the converging optical element 300 in the slow axis direction, thereby reducing the spot length of the laser beam array 610 at the convergence point along the slow axis direction. The second light shaping element 500 is disposed on the light-exiting side of the first light shaping element 400 and is used to compress the divergence angle of the laser beam array 620 emitted from the first light shaping element 400 in the fast axis direction, thereby increasing the spot length of the laser beam array 620 at the convergence point along the fast axis direction.

[0044] In this embodiment of the present invention, by providing a converging optical element 300, a first light shaping element 400, and a second light shaping element 500 in the laser light source, the laser beam array 610 generated by the laser array 200 is converged and light-shaped twice. This reduces the length of the light spot formed by the laser beam array 630 at the convergence point along the slow axis, while increasing the length of the light spot formed by the laser beam array 630 at the convergence point along the fast axis. This reduces the core diameter requirement of the light guide element, thereby reducing the cost of the light guide element.

[0045] In this embodiment, the first light shaping element 400 is further used to expand the divergence angle of each laser beam in the laser beam array 610 emitted from the converging optical element 300 in the slow axis direction.

[0046] In this embodiment, the laser light source further includes a light guide element 700 . The light guide element 700 is disposed on the light-emitting side of the second light shaping element 500 and is used to guide the laser beam array 630 .

[0047] In this embodiment, the ratio of the divergence angle of each laser beam in the laser beam array 630 emitted to the light guide element 700 in the fast axis direction to the divergence angle in the slow axis direction is greater than or equal to 0.8, such as 0.8, 0.9 or 1.

[0048] In this embodiment, the laser light source may further include a wavelength conversion device (not shown in the figure), which is disposed on the light-emitting side of the optical waveguide element 700 and is used to perform wavelength conversion on the laser beam array 630 .

[0049] In this embodiment, the light guide element 700 is described by taking an optical fiber as an example. In other embodiments, the light guide element 700 may also be an integrating rod, etc.

[0050] In this embodiment, the laser array 200 further includes a plurality of collimating lenses 220 corresponding one-to-one to the laser elements 210 . The collimating lenses 220 are used to collimate and adjust the laser beam array 610 .

[0051] See also Figure 6 In this embodiment, the laser element 210 is a long strip-shaped light-emitting chip, such as a semiconductor laser chip. The laser element 210 is provided with a light-emitting surface 211, which is arranged toward 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.

[0052] 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 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 of the laser element 210 may be 43° to 47°, such as 43°, 45°, or 47°. Because the divergence angle of the light-emitting surface 211 along the fast axis of the laser element 210 is greater than the divergence angle along the slow axis of the laser element 210, the plurality of laser elements 210 are generally arranged such that the spacing along the fast axis is greater than the spacing along the slow axis.

[0053] See also Figure 7 and Figure 8 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 is, where tanθ=d / f1.

[0054] In other embodiments, the collimating lens 220 may also be a plano-convex lens, which is not limited here.

[0055] 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 light spot formed at the convergence point by the laser beam array 610 along the slow axis is L, where L = d*f2 / f1.

[0056] In this embodiment, the first light shaping element 400 is a cylindrical lens array arranged along the slow axis. The cylindrical lens array includes a plurality of cylindrical lenses, each of which extends along the fast axis and is configured to receive the laser beam 610 generated by a corresponding row of lasers arranged along the fast axis.

[0057] In this embodiment, the cylindrical lens may be a plano-convex cylindrical lens, with its flat surface facing the converging optical element 300 and its convex surface facing away from the converging optical element 300. In other embodiments, the cylindrical lens may also be a biconvex cylindrical lens.

[0058] See also Figure 9In other embodiments, the geometric centers of the first light shaping elements 400 can also be located on the same curve, with the convex surface of the curve facing the converging optical element 300, so that each laser beam 610 is incident normally on the first light shaping element 400, thereby enabling each first light shaping element 400 to achieve a better light shaping effect. Compared to first light shaping elements 400 arranged in a straight line, laser beams passing through the cylindrical lenses in the edge area and those passing through the cylindrical lenses in the middle area can achieve a better converging effect.

[0059] See also Figure 4 、 Figure 5 、 Figure 10 and Figure 11 Because the length direction of the first light shaping element 400 is parallel to the fast axis direction, the first light shaping element 400 only converges the laser beam array 610 along the slow axis direction. This allows the total length of the light spot formed at the convergence point by the laser beam array 620 emitted from the first light shaping element 400 along the slow axis direction to be shorter than the total length of the light spot formed at the convergence point by the laser beam array 610 emitted from the converging optical element 300 along the slow axis direction. This helps to reduce the core diameter requirement of the optical fiber, thereby reducing the cost of the optical fiber.

[0060] According to the principle of conservation of etendue: as the cross-sectional area of ​​a beam is compressed, its divergence angle necessarily increases. Therefore, the divergence angle of the light spot formed by each laser beam 620 at the convergence point along the slow axis can be greater than the divergence angle of the light spot formed by each laser beam 610 at the convergence point along the slow axis. Furthermore, because the angle of the total beam of laser beam array 620 remains unchanged compared to laser beam array 610, the spatial angle spacing of the light spots formed by the multiple laser beam arrays 620 at the convergence point along the slow axis is reduced, resulting in a more uniform light spot formed by the laser beam arrays 620 at the convergence point.

[0061] See also Figure 12 and Figure 13 In this embodiment, the second light shaping element 500 may be a concave cylindrical lens, the length direction of which is parallel to the slow axis direction, and is used to receive the laser beam array 620 .

[0062] In this embodiment, the concave cylindrical lens may be a meniscus cylindrical lens, with the concave surface of the meniscus cylindrical lens facing 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. This can ensure that the total length of the light spot formed by the laser beam array 630 at the convergence point along the fast axis is greater than the total length of the light spot formed by the laser beam array 620 at the convergence point along the fast axis, and that the divergence angle of the light spot formed by each laser beam array 630 at the convergence point along the fast axis is smaller than the divergence angle of the light spot formed by each laser beam array 620 at the convergence point along the fast axis. As a result, the difference between the divergence angle of the light spot formed by the laser beam array 630 emitted to the optical fiber at the convergence point along the fast axis direction and the divergence angle along the slow axis direction is less than the angle threshold, and the divergence angle value is relatively small. The difference between the length of the light spot formed by the laser beam array 630 at the convergence point along the slow axis direction and the length along the fast axis direction is less than the length threshold, and the lengths are relatively small, which is further beneficial to reducing the requirements for the core diameter and NA of the optical fiber, thereby reducing the cost and setting difficulty of the optical fiber.

[0063] In other embodiments, the concave cylindrical lens may also be a plano-concave cylindrical lens, which is not limited here.

[0064] See also Figure 14 and Figure 15 In another specific embodiment, the laser light source may further include a third light shaping element 800, disposed between the laser array 200 and the converging optical element 300, for compressing the divergence angle of the laser beams generated by each row of lasers 210 arranged along the fast axis in the slow axis direction. The provision of the third light shaping element 800 prevents the divergence angle of the collimated laser beam from being too large, which could cause the beam to diverge onto adjacent first light shaping elements 400 upon exiting the converging optical element 300. This would cause mutual interference and result in an uneven light spot.

[0065] In this embodiment, the third light shaping element 800 is a cylindrical lens array, which includes a plurality of cylindrical lenses. Each cylindrical lens extends along the fast axis and is configured to receive laser beams generated by a row of lasers 210 arranged along the fast axis.

[0066] In this embodiment, the cylindrical lens may be a plano-convex cylindrical lens, with its flat surface facing the converging optical element 300 and its convex surface facing away from the converging optical element 300. In other embodiments, the cylindrical lens may also be a biconvex cylindrical lens.

[0067] See also Figure 16 and Figure 17In another specific embodiment, the laser light source may further include a fourth light shaping element 900, disposed between the converging optical element 300 and the first light shaping element 400, for compressing the divergence angle of the laser beams generated by each row of lasers 210 arranged along the fast axis in the slow axis direction. The provision of the fourth light shaping element 900 prevents the divergence angle of the collimated laser beam from being too large, which could result in the beams, when emitted from the converging optical element 300 to the corresponding first light shaping element 400, diverging to adjacent first light shaping elements 400, causing mutual interference and resulting in an uneven emitted light spot.

[0068] In this embodiment, the fourth light shaping element 900 is a cylindrical lens array, which includes a plurality of cylindrical lenses. Each cylindrical lens extends along the fast axis and is configured to receive laser beams generated by a corresponding row of lasers 210 arranged along the fast axis.

[0069] In this embodiment, the cylindrical lens may be a plano-convex cylindrical lens, with the flat surface of the plano-convex cylindrical lens facing away from the converging optical element 300 and the convex surface of the plano-convex cylindrical lens facing the converging optical element 300. In other embodiments, the cylindrical lens may also be a biconvex cylindrical lens.

[0070] In this embodiment, the focus 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 output end of the first light shaping element 400, that is, the first light shaping element 400 is located at a non-focal position of the fourth light shaping element 900.

[0071] See also Figure 18 and Figure 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. The structure and position of the third light shaping element 800 and the fourth light shaping element 900 are described in the aforementioned laser light source embodiment and are not further described here. The simultaneous provision of the third light shaping element 800 and the fourth light shaping element 900 allows for better control over the divergence angle of the laser beam, further reducing mutual interference.

[0072] The above description is only an embodiment of the present invention and does not limit the patent 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 in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A laser light source, characterized in that: include: A laser array comprising a plurality of laser elements arranged in a two-dimensional array, wherein the fast axis direction and the slow axis direction of the plurality of laser elements are the same, and is used to generate a laser beam array; A converging optical element, disposed on the light-emitting side of the laser array, for converging the laser beam array; a first light shaping element, disposed on the light-emitting side of the converging optical element, for converging the laser beam array emitted by the converging optical element in the slow axis direction, so as to reduce the spot length of the laser beam array at the convergence point along the slow axis direction; a second light shaping element, disposed on the light-emitting side of the first light shaping element, for compressing the divergence angle of the laser beam array emitted by the first light shaping element in the fast axis direction and enlarging the spot length of the laser beam array at the convergence point along the fast axis direction; Wherein, the first light shaping element is a cylindrical lens array, the cylindrical lens array includes a plurality of cylindrical lenses, each of the cylindrical lenses extends along the fast axis direction and is used to receive the laser beam generated by a corresponding row of lasers arranged along the fast axis direction; The geometric centers of the multiple cylindrical lenses are located on the same curve, and the convex surface of the curve faces the converging optical element.

2. The laser light source according to claim 1, wherein: The first light shaping element is further configured to expand the divergence angle of each laser beam in the laser beam array emitted from the converging optical element in the slow axis direction.

3. 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.

4. The laser light source according to claim 1, wherein: The laser light source further includes a third light shaping element, which is disposed between the laser array and the converging optical element and is configured to compress, in the slow axis direction, the divergence angle of the laser beams generated by each row of lasers arranged along the fast axis direction.

5. The laser light source according to claim 4, characterized in that: The third light shaping element is a cylindrical lens array, which includes a plurality of cylindrical lenses. Each cylindrical lens extends along the fast axis and is used to receive a laser beam generated by a corresponding row of lasers arranged along the fast axis.

6. The laser light source according to claim 1 or 4, characterized in that: The laser light source further includes a fourth light shaping element, which is disposed between the converging optical element and the first light shaping element and is configured to compress, in a slow axis direction, the divergence angle of the laser beams generated by each row of lasers arranged along a fast axis.

7. The laser light source according to claim 6, wherein: The fourth light shaping element is a cylindrical lens array, which includes a plurality of cylindrical lenses. Each cylindrical lens extends along the fast axis and is used to receive a laser beam generated by a corresponding row of lasers arranged along the fast axis.

8. The laser light source according to claim 1, wherein The laser light source further includes a light guide element, which is disposed on the light-emitting side of the second light shaping element and is used to guide the laser beam array emitted by the second light shaping element.

9. The laser light source according to claim 1, wherein: The laser array further includes a plurality of collimating lenses corresponding one-to-one to the laser elements, and the collimating lenses are used to collimate and adjust the laser beam array emitted by the plurality of laser elements.

Images