Laser light source and machining device

Abstract

A laser light source, comprising: a laser unit (1), used for emitting a laser beam (10), the laser beam (10) having a first divergence angle in a fast axis direction and having a second divergence angle in a slow axis direction, and the first divergence angle being greater than the second divergence angle; a collimating element (3), arranged on an optical path of the laser beam (10) and used for collimating the laser beam (10) in the fast axis direction of the laser beam (10); a diffusion element (4), used for receiving the laser beam (10) from the collimating element (3) and diffusing the laser beam (10) in the fast axis direction of the laser beam (10), so as to increase the divergence angle of the laser beam (10) to a third divergence angle, the third divergence angle being smaller than the first divergence angle; and a focusing element (2), used for focusing the laser beam (10) from the diffusion element (4). The laser light source can increase the power density of a focusing point. The present application further relates to a machining device having the laser light source.

Description

Laser light source and processing equipment

Technical field

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

[0002] It is known that a laser beam has a fast axis direction and a slow axis direction. The expansion of the laser beam in the fast axis direction is greater than the expansion of the laser beam in the slow axis direction. Therefore, the laser beam forms an elliptical spot when traveling to the far field, that is, the spot size of the laser beam in the fast axis direction is greater than the spot size of the laser beam in the slow axis direction.

[0003] In scenarios such as laser processing, the laser beam is typically collimated in both its fast and slow axes, and then focused to the same point using a condenser lens. However, this optical path has certain drawbacks: the spot size corresponding to the fast axis at the focused point is significantly larger than the spot size corresponding to the slow axis at the focused point, resulting in a relatively low power density at the focused point.

[0004] [Summary of the invention]

[0005] The purpose of this application is to provide a laser light source to increase the power density of the laser beam at the focus point.

[0006] To achieve the above objectives, in a first aspect, embodiments of the present application provide a laser light source, comprising:

[0007] a laser unit configured to emit a laser beam, wherein the laser beam has a first divergence angle in a fast axis direction and a second divergence angle in a slow axis direction, wherein the first divergence angle is greater than the second divergence angle;

[0008] a collimating element, disposed on an optical path of the laser beam, and configured to collimate the laser beam in a fast axis direction of the laser beam;

[0009] a diffusion element, configured to receive the laser beam from the collimating element and diffuse the laser beam in a fast axis direction of the laser beam so that a divergence angle of the laser beam is increased to a third divergence angle, wherein the third divergence angle is smaller than the first divergence angle; and

[0010] A focusing element is used to focus the laser beam from the diffusion element.

[0011] In some possible implementations, the diffusion element includes an optical medium, the optical medium is used to transmit the laser beam, and an optical curved surface is provided on the optical medium for diffusing the laser beam in a fast axis direction.

[0012] In some possible implementations, the optical curved surface is a curve on a cross section determined by the fast axis direction of the laser beam, and the optical curved surface is a straight line on a cross section determined by the slow axis direction of the laser beam.

[0013] In some possible implementations, the optical curved surface is provided on the light incident surface of the optical medium, and the optical curved surface is curved toward the interior of the optical medium.

[0014] In some possible implementations, the light-emitting surface of the optical medium is configured to be a plane.

[0015] In some possible embodiments, a light directing element is further included, including a plurality of laser units, wherein the plurality of laser units are configured to emit a plurality of laser beams, and the plurality of laser beams are all incident on the diffusion element, wherein the plurality of laser beams are symmetrical about the central axis of the diffusion element.

[0016] In some possible implementations, a light directing element is further included, which is disposed between the diffusion element and the collimating element and is used to change the traveling direction of the laser beam.

[0017] In some possible embodiments, the diffusion element is located on the optical axis of the focusing element, and the position of the diffusion element relative to the focusing element is adjustable so that the intersection point of the extension line of the fast axis direction of the laser beam and the intersection point of the slow axis direction of the laser beam are located at the same point.

[0018] In some possible embodiments, the diffusion element is located on the optical axis of the focusing element, and the position of the diffusion element relative to the focusing element is adjustable so that the size of the spot of the laser beam incident on the focusing element is substantially the same in the fast axis direction and the slow axis direction.

[0019] In a second aspect, an embodiment of the present application provides a processing device comprising the laser light source as described above.

[0020] Beneficial effects of this application:

[0021] The laser light source of the embodiment of the present application is provided with a collimating element and a diffusing element between the laser unit and the focusing element, which are used to collimate and diffuse the fast axis direction of the laser beam, thereby reducing the size of the light spot in the fast axis direction that converges to the focal point through the focusing element, so as to increase the power density at the focal point.

Brief Description of the Drawings

[0022] 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:

[0023] FIG1 is a schematic diagram of the optical path structure of a laser light source in a first direction according to an embodiment of the present application;

[0024] FIG2 is a schematic diagram of the optical path structure of the laser light source in the second direction according to an embodiment of the present application. [Specific implementation method]

[0025] 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] 1 and 2 , an embodiment of the present application provides a laser light source, including a laser unit 1 , a focusing element 2 , a collimating element 3 and a diffusion element 4 .

[0027] The laser unit 1 includes a semiconductor laser element, such as a laser diode, and is used to emit a laser beam 10 , wherein the laser beam 10 has a first divergence angle in the fast axis direction and a second divergence angle in the slow axis direction, wherein the first divergence angle is greater than the second divergence angle.

[0028] The focusing element 2 is disposed in the optical path of the laser beam 10 and is used to focus the laser beam 10 to a focal point 200. The focusing element 2 can be a focusing lens, which can converge the incident laser beam 10 to the focal point 200 behind the focusing lens. In some optional examples, the focusing element 2 can be a single lens element or a cascade of multiple lens elements.

[0029] The collimating element 3 is disposed on the outgoing optical path of the laser beam 10 and is used to collimate the laser beam 10 in the fast axis direction of the laser beam 10. The collimating element 3 can be, for example, a cylindrical lens, which has collimation in the fast axis direction of the laser beam 10 and does not change the divergence angle of the laser beam 10 in the slow axis direction.

[0030] The diffusion element 4 is arranged in the optical path of the laser beam 10 between the collimating element 3 and the focusing element 2. The diffusion element 4 is used to diffuse the laser beam 10 in the fast axis direction of the laser beam 10 and expand the divergence angle of the laser beam 10 in the fast axis direction to a third divergence angle, wherein the third divergence angle is smaller than the first divergence angle.

[0031] In related technologies, after collimating the laser beam in both the fast and slow axis directions, the laser beam is focused to a focal point using a focusing element. Since the fast-axis direction of the light spot emitted by the laser beam after fast-axis collimation is relatively small, the fast-axis direction of the light spot focused at the focal point by the focusing element is larger, resulting in a lower power density. In the embodiments of the present application, after collimating the laser beam in the fast axis direction, the divergence angle of the laser beam in the fast axis direction is expanded using a diffusion element, resulting in a smaller fast-axis direction of the light spot focused at the focal point by the focusing element, thereby increasing the power density at the focal point.

[0032] It can be understood that after being collimated in the fast axis direction by the collimating element 3, the laser beam 10 is changed in the fast axis direction to travel toward the focusing element 2 in the form of parallel light or nearly parallel light. At this time, the laser beam 10 in the fast axis direction is equivalent to a point light source emitted from a luminous point at infinity. In order to make the focusing element 2 converge the fast axis direction and slow axis direction of the laser beam 10 to the same focal point 200, one way is to also collimate the slow axis direction of the laser beam 10. This is adopted in the relevant technology, but this will cause the fast axis direction of the light spot at the focal point to be larger, and thus the power density to be lower. In the embodiment of the present application, after being collimated in the fast-axis direction by the collimating element 3, the laser beam 10 is again passed through the diffusing element 4 to expand the divergence angle of the laser beam 10 in the fast-axis direction, so that the laser beam is projected onto the focusing element 2 at a third divergence angle that is smaller than the first divergence angle. Thus, after passing through the diffusing element 4, the reverse extensions of the various rays of the laser beam 10 in the fast-axis direction converge at an intersection point, i.e., the laser beam 10 in the fast-axis direction is equivalent to a diverging beam emitted from this intersection point. Therefore, while the size of the spot where the laser beam 10 in the fast-axis direction converges to the focal point through the focusing element 2 decreases, the position of the focal point where the laser beam 10 in the fast-axis direction converges through the focusing element 2 also changes.

[0033] In the embodiment of the present application, the laser beam 10 is configured to project a divergent beam in the slow axis direction onto the focusing element 2 and converge to a focal point through the focusing element 2. In the slow axis direction of the laser beam 10, it is equivalent to a divergent beam projected from a light point onto the focusing element 2.

[0034] By configuring the position of the diffuser element 4 on the optical axis of the focusing element 2, the position of the equivalent luminous point of the laser beam 10 in the fast axis direction can be configured. For example, when the diffuser element 4 moves on the optical axis of the focusing element 2, the position of the equivalent luminous point of the laser beam 10 in the fast axis direction changes synchronously with the position of the diffuser element 4, while the position of the equivalent luminous point of the laser beam 10 in the slow axis direction can remain unchanged. Therefore, the position of the diffuser element 4 on the optical axis of the focusing element 2 can be configured so that the equivalent luminous point of the laser beam 10 in the fast axis direction and the equivalent luminous point of the laser beam 10 in the slow axis direction are located at the same point. In this way, after passing through the focusing element 2 in both the fast axis direction and the slow axis direction, the laser beam 10 is focused to the same focal point 200.

[0035] By configuring the size of the divergence ability of the diffusion element 4 in the fast axis direction of the laser beam, the position of its equivalent luminous point can be configured. For example, when the divergence ability of the diffusion element 4 in the fast axis direction of the laser beam is greater, the equivalent luminous point in the fast axis direction of the laser beam will be further away from the focusing element 2, and conversely closer to the focusing element 2, thereby enabling the position of the equivalent luminous point of the laser beam 10 to be configured. On the other hand, by configuring the size of the divergence ability of the diffusion element 4 in the fast axis direction of the laser beam, the divergence angle of the laser beam 10 in the fast axis direction, that is, the size of the third divergence angle, can be configured. When the size of the third divergence angle is the same as or close to the second divergence angle (the divergence angle in the slow axis direction of the laser beam 10), and the equivalent luminous point of the laser beam 10 in the fast axis direction and the equivalent luminous point in the slow axis direction are located at the same point, the laser beam 10 is focused to the same focal point 200 after passing through the focusing element 2. The focusing point 200 forms a circular light spot, that is, a light spot that is substantially equal in the fast axis direction and the slow axis direction. Therefore, the power density of the focusing point 200 is improved.

[0036] In some embodiments, the diffusion element 4 includes an optical medium 400 having a light incident surface 401 and a light emitting surface 402. The laser beam 10 is incident on the light incident surface 401 of the optical medium 400, propagates within the optical medium 400, and is ultimately emitted from the light emitting surface 402 of the optical medium 400. The optical medium 400 can be made of a light-transmitting material such as glass, plastic, or PVC.

[0037] The optical medium 400 is used to transmit the laser beam 10. An optical curved surface 403 is formed on the optical medium 400 to diffuse the laser beam 10 in the fast axis direction. That is, the laser beam 10 that has been collimated in the fast axis direction by the collimating element 2 is diffused in the fast axis direction by the optical curved surface 403 formed on the optical medium 400 when it enters the optical medium 400, thereby increasing the divergence angle of the laser beam 10 in the fast axis direction and making the increased third divergence angle smaller than the initial first divergence angle.

[0038] In some embodiments, the optical surface 403 is configured to be a curve on the cross-section determined by the fast axis direction of the laser beam 10 (the cross-section shown in FIG1 ), so that when the laser beam 10 passes through the optical surface 403, the optical surface 403 uses its curved structure to expand the divergence angle of the laser beam 10 in the fast axis direction; the optical surface 403 can also be configured to be a straight line on the cross-section determined by the slow axis direction of the laser beam 10 (the cross-section shown in FIG2 ), so that when the laser beam 10 passes through the optical surface 403, the angle of the laser beam 10 in the slow axis direction only changes due to refraction, and this part of the angle change can eventually be eliminated due to emission from the light-emitting surface 402 of the optical medium 400. For example, in some embodiments, the light-emitting surface 402 of the optical medium 400 is configured to be a plane.

[0039] In some embodiments, the optical curved surface 403 is disposed on the light incident surface of the optical medium 400 and is curved toward the interior of the optical medium 400. That is, the optical curved surface 403 is configured as a concave structure formed on the light incident surface 401 of the optical medium 400. After being collimated along the fast axis, the laser beam 10 is incident on the concave structure as parallel or nearly parallel light along the fast axis, thereby diffusing the laser beam 10 along the fast axis. The extended line of the diffused laser beam 10 along the fast axis intersects with, or is close to intersecting with, the center of curvature of the concave structure. Thus, after passing through the optical curved surface 403, the laser beam 10 along its fast axis is equivalent to a laser beam projected toward the focusing element 2 with the center of curvature as the luminous point.

[0040] In some embodiments, the light-emitting surface 402 of the optical medium 400 is configured as a plane. Therefore, the optical medium 400 as a whole exhibits the shape of a concave cylindrical element, which can expand the divergence angle of the laser beam 10 in the fast axis direction of the laser beam 10 and transmit the laser beam 10 in the slow axis direction without changing the divergence angle of the laser beam 10.

[0041] In some embodiments, the laser light source includes multiple laser units 1 , each of which emits multiple laser beams 10 , and all of the multiple laser beams 10 enter the diffusion element 4 , wherein the multiple laser beams 10 are symmetrical about the central axis of the diffusion element.

[0042] Specifically, multiple laser units 1 each emit multiple laser beams 10. Each of the multiple laser beams 10 passes through a collimating element 3 and is collimated along its fast axis. The multiple laser beams 10 then enter a diffusion element 4. After the diffusion element 4 expands the divergence angle of each laser beam 10 along its fast axis, the laser beams 10 are focused onto a single focal point 200 by a concentrating element 2. Because the laser beams 10 emitted by multiple laser units 1 are simultaneously focused onto a single focal point 200 in this embodiment, the power density at the focal point 200 is further increased.

[0043] The central axis of the diffusion element 4 can be understood as a straight line defined by the optical axis of the diffusion element 4, or, for example, a straight line defined by the geometric central axis of the diffusion element 4 in its structure as shown in FIG1 . The multiple laser beams 10 emitted by the multiple laser units 1 are arranged symmetrically about the central axis of the diffusion element 4. In this way, the light spots of the multiple laser beams 10 incident on the diffusion element 4 combine to form a circular light spot area, and are ultimately focused to the same focal point 200 by the focusing element 2.

[0044] In some specific examples, the number of laser units 1 can be set to two, the laser beams 10 emitted by each of the two laser units 1 have the same fast axis direction and slow axis direction, and the two laser units 1 are arranged along the fast axis direction of the laser beams 10 they emit, and the two laser beams 10 are symmetrical about the central axis of the diffusion element 4.

[0045] In some embodiments, the laser light source further includes a light directing element 5 disposed between the collimating element 3 and the diffusing element 4 for changing the direction of the laser beam 10. For example, as shown in FIG1 , the laser unit 1 emits a laser beam 10 in a horizontal direction. After fast-axis collimation is performed by the collimating element 3 , the laser beam 10 is redirected by the light directing element 5 . The direction of the laser beam 10 is changed upwards, and the laser beam 10 is incident upwards on the diffusing element 4 . By changing the direction of the laser beam 10, the spatial volume is rationally utilized, and the overall volume is reduced.

[0046] In some specific examples, the light-directing element 5 may be a reflective element, such as a reflective mirror. In the example shown in FIG1 , the light-directing element 5 is a reflective prism having multiple reflective surfaces, and thus can simultaneously reflect multiple laser beams 10 emitted by multiple laser units 1. It should be noted that in other examples, the light-directing element 5 may be integrated with the collimating element 3. For example, a concave reflective element may be provided between the laser unit 1 and the diffusion element 4. The concave reflective element has a curvature in the fast axis direction of the laser beam 10 to collimate and reflect the laser beam 10 in the fast axis direction of the laser beam 10. The concave reflective element has no curvature in the slow axis direction of the laser beam 10, or is a straight line relative to the slow axis direction of the laser beam 10, and thus only reflects the laser beam 10 in the slow axis direction of the laser beam 10. In this way, the concave reflective element simultaneously achieves the functions of collimating the fast axis direction of the laser beam 10 and changing the traveling direction of the laser beam 10.

[0047] In some embodiments, laser unit 1 can be a laser chip, such as an edge-emitting semiconductor laser chip. This allows the bottom surface of laser unit 1 to have a large surface area, allowing it to be mounted on a thermal layer structure and maintain a large contact area with the thermal layer structure, thereby achieving good heat dissipation. Surface mounting the bottom surface of this laser chip and emitting the laser beam from the side allows for SMD packaging of the laser chip, which helps reduce overall size.

[0048] As described above, by configuring the position of the diffuser element 4 on the optical axis of the focusing element 2, the position of the equivalent light-emitting point of the laser beam 10 can be configured along the fast axis. In some embodiments, the diffuser element 4 can be positioned on the optical axis of the focusing element 2, and the position of the diffuser element 2 relative to the focusing element 2 can be adjusted.

[0049] In some embodiments, the position of the diffusion element 4 relative to the focusing element 2 is adjusted so that the intersection point defined by the extension of the fast axis of the laser beam 10 after diffusion by the diffusion element 4 and the intersection point defined by the slow axis of the laser beam 10 are located at the same point. In this way, the laser beam 10 is equivalent to being projected from the same point and is therefore focused by the focusing element 2 to the same focal point 200, thereby increasing the power density at the focal point 200.

[0050] In some embodiments, the position of the diffusion element 4 relative to the focusing element 2 is adjusted so that the spot size of the laser beam 10 incident on the focusing element 2 is substantially the same in both the fast and slow axis directions. This allows the laser beam 10 to form a circular spot as much as possible. As a result, the focused point 200 formed after passing through the focusing element 2 forms a spherical space. Therefore, the spot size of the focused point 200 is substantially the same in all directions, thereby increasing the power density at the focused point 200.

[0051] In some embodiments, the position of the diffusion element 4 relative to the focusing element 2 is adjusted so that the divergence angles of the laser beam 10 incident on the focusing element 2 are substantially equal in the fast and slow axis directions. This also helps to form the laser beam 10 into a circular spot as much as possible. As a result, the spot size of the focused point 200 after passing through the focusing element 2 is substantially the same in all directions, thereby increasing the power density at the focused point 200.

[0052] In some embodiments, the laser light source includes an adjustment element (not shown) connected to the diffusion element 4 to drive the diffusion element 4 to move along the optical axis of the focusing element 2. Thus, the position of the diffusion element 4 along the optical axis of the focusing element 2 can be adjusted by the adjustment element. The adjustment element can be, for example, a position adjustment structure such as an electric slider, a manual slider, or a threaded push rod.

[0053] An embodiment of the present application also provides a processing device, comprising the laser light source as described above.

[0054] The processing device is used, for example, in scenarios where high-energy laser processing is performed, such as laser cutting and laser engraving used in industrial processing, medical cosmetology, and the like.

[0055] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A laser light source, characterized in that: include: A laser unit, configured to emit a laser beam, wherein the laser beam has a first divergence angle in a fast axis direction and a second divergence angle in a slow axis direction, wherein the first divergence angle is greater than the second divergence angle; A collimating element, disposed on an optical path of the laser beam, and used to collimate the laser beam in a fast axis direction of the laser beam; a diffusion element, used for receiving the laser beam from the collimating element and diffusing the laser beam in the fast axis direction of the laser beam so that the divergence angle of the laser beam is increased to a third divergence angle, wherein the third divergence angle is smaller than the first divergence angle; as well as A focusing element is used to focus the laser beam from the diffusion element.

2. The laser light source according to claim 1, characterized in that: The diffusion element includes an optical medium, the optical medium is used to transmit the laser beam, and an optical curved surface for diffusing the laser beam in a fast axis direction is arranged on the optical medium.

3. The laser light source according to claim 2, characterized in that: The optical curved surface is a curve on a cross section determined by the fast axis direction of the laser beam, and the optical curved surface is a straight line on a cross section determined by the slow axis direction of the laser beam.

4. The laser light source according to claim 2, characterized in that: The optical curved surface is arranged on the light incident surface of the optical medium, and the optical curved surface is curved toward the inside of the optical medium.

5. The laser light source according to claim 4, characterized in that: The light emitting surface of the optical medium is arranged to be a plane.

6. The laser light source according to claim 1, characterized in that: It comprises a plurality of laser units, and the plurality of laser units are used to emit a plurality of laser beams, and the plurality of laser beams are all incident on the diffusion element, wherein the plurality of laser beams are symmetrical about the central axis of the diffusion element.

7. The laser light source according to claim 1 or 6, characterized in that: A light directing element is also included, which is disposed between the diffusion element and the collimating element and is used to change the traveling direction of the laser beam.

8. The laser light source according to claim 1, characterized in that: The diffusion element is located on the optical axis of the focusing element, and the position of the diffusion element relative to the focusing element is adjustable so that the intersection point of the extension line of the fast axis direction of the laser beam and the intersection point of the slow axis direction of the laser beam are located at the same point.

9. The laser light source according to claim 1, characterized in that: The diffusion element is located on the optical axis of the focusing element, and the position of the diffusion element relative to the focusing element is adjustable so that the size of the light spot of the laser beam incident on the focusing element in the fast axis direction and the slow axis direction is substantially the same.

10. A processing device, characterized in that: Comprising the laser light source as claimed in any one of claims 1 to 9.

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