Laser light source and processing apparatus

Abstract

The invention discloses a laser light source and a processing device, and belongs to the technical field of laser processing. The laser light source comprises a laser unit used for emitting a laser beam, the laser beam has a first divergence angle in the fast axis direction and has a second divergence angle in the slow axis direction, and the first divergence angle is larger than the second divergence angle; the collimating element is arranged on a light path of the laser beam and is used for collimating the laser beam in the fast axis direction of the laser beam; the diffusion element is 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, and the third divergence angle is smaller than the first divergence angle; and a light focusing element for focusing the laser beam from the diffusion element. The laser light source can improve the power density of the focus point.

Description

[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, and 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 in the fast axis direction of the laser beam is greater than the spot size in the slow axis direction of the laser beam.

[0003] In laser processing scenarios, the fast and slow axis directions of the laser beam are usually collimated, and then the collimated laser beams in both the fast and slow axis directions are focused to the same point through a condenser lens. However, this optical path has certain shortcomings: the light spot corresponding to the fast axis direction at the focus point is significantly larger than the light spot corresponding to the slow axis direction at the focus point, resulting in a relatively low power density at the focus point. [Summary of the invention]

[0004] The purpose of the present application is to provide a laser light source to increase the power density of the laser beam at a focusing point.

[0005] To achieve the above objectives, in a first aspect, an embodiment of the present application provides a laser light source, including:

[0006] 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;

[0007] 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;

[0008] 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

[0009] A focusing element is used to focus the laser beam from the diffusion element.

[0010] 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 for diffusing the laser beam in a fast axis direction is provided on the optical medium.

[0011] In some possible implementations, the optical curved surface is a curve on the cross section determined by the fast axis direction of the laser beam, and the optical curved surface is a straight line on the cross section determined by the slow axis direction of the laser beam.

[0012] In some possible implementations, the optical curved surface is disposed on the light incident surface of the optical medium, and the optical curved surface is curved toward the interior of the optical medium.

[0013] In some possible implementations, the light emitting surface of the optical medium is set to be a plane.

[0014] In some possible embodiments, a light directing element is further included, including a plurality of laser units, wherein 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.

[0015] In some possible implementations, a light directing element is further included, which is disposed between the diffusion element and the collimation element and is used to change the traveling direction of the laser beam.

[0016] 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.

[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 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.

[0018] In a second aspect, an embodiment of the present application provides a processing device, comprising the laser light source as described above.

[0019] Beneficial effects of this application:

[0020] 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 focusing point through the focusing element, so as to increase the power density at the focusing point.

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. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0022] Figure 1This is a schematic diagram of the optical path structure of the laser light source in the first direction according to an embodiment of the present application;

[0023] Figure 2 Schematic diagram of the optical path structure in the second direction of the laser light source in an embodiment of the present application. [Specific implementation method]

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0025] Please refer to Figure 1 and Figure 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 diffusing element 4.

[0026] 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.

[0027] The focusing element 2 is arranged on 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 selected as a focusing lens, which can gather the incident laser beam 10 to the focal point 200 behind the focusing lens. In some optional examples, the focusing element 2 can be selected as a single lens element or a plurality of cascaded lens elements.

[0028] The collimating element 3 is arranged 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.

[0029] The diffusion element 4 is arranged on 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.

[0030] In the related art, after the laser beam is collimated in the fast axis direction and the slow axis direction, the laser beam is converged to the focal point through the focusing element. Since the fast axis direction of the light spot emitted after the laser beam is collimated in the fast axis direction is relatively small, the fast axis direction of the light spot converged at the focal point by the focusing element is larger, resulting in a lower power density. In the embodiment of the present application, after the laser beam is collimated in the fast axis direction, the divergence angle of the laser beam in the fast axis direction is expanded by the diffusion element, so that the fast axis direction of the light spot converged at the focal point by the focusing element is reduced, thereby improving the power density of the focal point.

[0031] 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 as 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 light 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 focusing point 200, one of the ways 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 of the focusing point to be larger, thereby reducing the power density. In the embodiment of the present application, the laser beam 10, after being collimated in the fast axis direction by the collimating element 3, passes through the diffusing element 4 again to expand the divergence angle of the laser beam 10 in the fast axis direction, so that the laser beam is projected to the focusing element 2 at a third divergence angle smaller than the first divergence angle. In this way, after passing through the diffusing element 4, the reverse extension lines of the various light rays of the laser beam 10 in the fast axis direction converge at an intersection point, that is, the laser beam 10 in the fast axis direction is equivalent to a divergent light beam emitted with the intersection point as the light-emitting point. Therefore, while the size of the light spot of the laser beam 10 in the fast axis direction through the focusing element 2 is reduced, the position of the focusing point of the laser beam 10 in the fast axis direction through the focusing element 2 is also changing.

[0032] In the embodiment of the present application, the laser beam 10 is configured to be projected onto the focusing element 2 as a divergent beam in the slow axis direction, and converged to a focal point through the focusing element 2. In the slow axis direction of the laser beam 10, it can be equivalent to a divergent beam projected onto the focusing element 2 as a light point.

[0033] By configuring the position of the diffusion element 4 on the optical axis of the focusing element 2, the position of the equivalent luminous point of the laser beam 10 can be configured in the fast axis direction. For example, when the diffusion 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 diffusion 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 diffusion 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, so that the laser beam 10 in the fast axis direction and the slow axis direction are focused on the same focal point 200 after passing through the focusing element 2.

[0034] 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 on the contrary, closer to the focusing element 2, so that the position of the equivalent luminous point of the laser beam 10 can 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 focusing 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.

[0035] In some embodiments, the diffusion element 4 includes an optical medium 400, and the optical medium 400 has a light incident surface 401 and a light emitting surface 402. The laser beam 10 is incident from the light incident surface 401 of the optical medium 400 to the inside of the optical medium 400, propagates inside the optical medium 400, and finally exits from the light emitting surface 402 of the optical medium 400. The optical medium 400 can be selected from a light-transmitting material such as glass, plastic, or PVC.

[0036] The optical medium 400 is used to transmit the laser beam 10, and an optical curved surface 403 for diffusing the laser beam 10 in the fast axis direction is formed on the optical medium 400. 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, so as to increase the divergence angle of the laser beam 10 in the fast axis direction, and make the increased third divergence angle smaller than the initial first divergence angle.

[0037] In some embodiments, the optical curved surface 403 is configured to be a curve (eg, Figure 1 When the laser beam 10 passes through the optical curved surface 403, the optical curved surface 403 uses its curved structure to expand the divergence angle of the laser beam 10 in the fast axis direction; the optical curved surface 403 can also be set to be a straight line on the cross section determined by the slow axis direction of the laser beam 10 (such as Figure 2 In this way, when the laser beam 10 passes through the optical curved 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 be eventually eliminated due to the 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 set to a plane.

[0038] In some embodiments, the optical curved surface 403 is disposed on the light incident surface of the optical medium 400, and the optical curved surface 403 is curved toward the inside of the optical medium 400, that is, the optical curved surface 403 is disposed as a concave structure formed on the light incident surface 401 of the optical medium 400. After being collimated in the fast axis direction, the laser beam 10 is incident on the concave structure as parallel light or nearly parallel light in the fast axis direction, thereby diffusing the fast axis direction of the laser beam 10. The extended line of the laser beam 10 in the fast axis direction intersects with the center of curvature of the concave structure, or is close to intersecting with the center of curvature of the concave structure. In this way, after passing through the optical curved surface 403, the laser beam 10 in its fast axis direction is equivalent to a laser beam projected toward the focusing element 2 with the center of curvature as the light-emitting point.

[0039] In some embodiments, the light emitting surface 402 of the optical medium 400 is set to be a plane. Therefore, the optical medium 400 as a whole is in 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 of the laser beam 10 without changing the divergence angle of the laser beam 10.

[0040] In some embodiments, the laser light source includes a plurality of laser units 1 , each of which emits a plurality of laser beams 10 , and the plurality of laser beams 10 all enter the diffusion element 4 , wherein the plurality of laser beams 10 are symmetrical about the central axis of the diffusion element.

[0041] Specifically, multiple laser units 1 emit multiple laser beams 10 respectively, and the multiple laser beams 10 pass through the collimating element 3 and are collimated in the fast axis direction respectively, and then the multiple laser beams 10 are incident on the diffusion element 4, and after the divergence angle of each laser beam 10 in the fast axis direction is expanded by the diffusion element 4, they are focused to the same focal point 200 by the focusing element 2. Since the laser beams 10 emitted by multiple laser units 1 are focused to the same focal point 200 at the same time in this embodiment, the power density of the focal point 200 is further improved.

[0042] The central axis of the diffusion element 4 can be understood as a straight line determined by the optical axis of the diffusion element 4, or as Figure 1 In the structure of the diffusion element 4 shown in the figure, the straight line determined by the geometric center axis thereof is configured to emit multiple laser beams 10 symmetrically to the center axis of the diffusion element 4, so that the light spots of the multiple laser beams 10 incident on the diffusion element 4 are combined to form a circular light spot area, and therefore, are finally focused to the same focusing point 200 through the focusing element 2.

[0043] 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.

[0044] In some embodiments, the laser light source further includes a light directing element 5, which is disposed between the collimating element 3 and the diffusing element 4 and is used to change the traveling direction of the laser beam 10. Figure 1 As shown, the laser unit 1 emits a laser beam 10 in a horizontal direction, and after the laser beam 10 passes through the collimating element 10 for fast axis collimation 10, the traveling direction of the laser beam 10 is changed through the light guiding element 5, and the traveling direction of the laser beam 10 is changed to be directed upward, and incident upward to the diffusion element 4. By changing the direction of the laser beam 10, the spatial volume is reasonably utilized and the overall volume is reduced.

[0045] In some specific examples, the light directing element 5 may be a reflective element, such as a reflector. Figure 1In the example shown, the light-guiding element 5 is selected as a reflective prism, which has multiple reflective surfaces, so it can simultaneously reflect multiple laser beams 10 emitted by multiple laser units 1. It should be noted that in some other examples, the light-guiding element 5 may be integrated with the collimating element 3, for example, a concave reflective element is arranged between the laser unit 1 and the diffusion element 4, and 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, so it only reflects the laser beam 10 in the slow axis direction of the laser beam 10. In this way, the concave reflective element simultaneously realizes the collimation of the fast axis direction of the laser beam 10 and the effect of changing the traveling direction of the laser beam 10.

[0046] In some embodiments, the laser unit 1 may be a laser chip, such as an edge-emitting semiconductor laser chip. Therefore, the bottom surface of the laser unit 1 has a large area, and can be installed on a thermal layer structure and maintain a large contact area with the thermal layer structure, thereby obtaining good heat dissipation capability. The bottom surface of the laser chip is surface mounted, and the laser beam is emitted from the side, so that the SMD packaging of the laser chip can be realized, which is conducive to reducing the overall volume.

[0047] As described above, by configuring the position of the diffusion 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 in the fast axis direction. In some embodiments, the diffusion element 4 can be arranged on the optical axis of the focusing element 2, and the position of the diffusion element 2 relative to the focusing element 2 can be adjusted.

[0048] In some embodiments, the position of the diffusion element 4 relative to the focusing element 2 is adjusted so that the intersection point determined by the extension line of the fast axis direction of the laser beam 10 after being diffused by the diffusion element 4 and the intersection point determined by the slow axis direction 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 of the focal point 200.

[0049] In some embodiments, the position of the diffusion element 4 relative to the focusing element 2 is adjusted so that the spot sizes of the laser beam 10 incident on the focusing element 2 in the fast axis direction and the slow axis direction are substantially the same. In this way, the laser beam 10 can form a circular spot as much as possible, so that the focus point 200 focused after passing through the focusing element 2 forms a spherical space, so the spot sizes of the focus point 200 in all directions are substantially the same, so that the power density of the focus point 200 is improved.

[0050] 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 in the fast axis direction and the slow axis direction are substantially equal. This is also conducive to forming a circular spot of the laser beam 10 as much as possible, so that the spot size of the focus point 200 focused by the focusing element 2 is substantially the same in all directions, so that the power density of the focus point 200 is improved.

[0051] In some embodiments, the laser light source includes an adjustment element (not shown), which is connected to the diffusion element 4 to drive the diffusion element 4 to move on the optical axis of the focusing element 2. Thus, the position of the diffusion element 4 on 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.

[0052] An embodiment of the present application also provides a processing device, including the laser light source as described above.

[0053] The processing device is used, for example, in scenarios where high-energy laser processing is performed, such as laser cutting, laser engraving, etc. used in industrial processing, medical cosmetology, and the like.

[0054] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope 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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