CN114247988B

CN114247988B - Laser light source

Info

Publication number: CN114247988B
Application number: CN202011006388.8A
Authority: CN
Inventors: 千国达朗; 牛增强; 陈国宁; 卢国杰; 韩金龙
Original assignee: United Winners Laser Co Ltd
Current assignee: United Winners Laser Co Ltd
Priority date: 2020-09-23
Filing date: 2020-09-23
Publication date: 2024-05-10
Anticipated expiration: 2040-09-23
Also published as: CN114247988A

Abstract

The invention provides a laser light source comprising a plurality of LD modules and a plurality of collimating lenses for collimating light emitted from the LD modules, wherein the plurality of LD modules and the plurality of collimating lenses are arranged in a matrix in a container, mutually orthogonal X, Y, Z axes are provided in the matrix array, and the spacing between the reflecting mirrors of the stacking mirrors stacked in the SLOW axis direction is minimized by tilting reflection in the SLOW axis direction of the collimated light emitted from the LD modules in the Z axis direction, so that a dense laminated light beam with almost no gap in the Z axis direction is obtained.

Description

Laser light source

Technical Field

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

Background

In recent years, as a method for reducing the occurrence of spatter, blowholes, and the like during welding, which is an important research direction, the application of a conventional near infrared dual-core fiber laser has been expanding, and the dual-core fiber laser has been comprising a high-brightness central beam and a low-brightness ring beam, wherein the central beam can rapidly generate a keyhole, and the ring beam can heat a region around the keyhole, so that hybrid welding of both keyhole welding and thermal conduction type welding can be performed simultaneously. The mixed welding process is also heated in the area around the keyhole, so that the surface tension of the keyhole opening is increased, the keyhole opening can be unfolded like a bell mouth, and metal vapor can be smoothly discharged, so that splashing can be greatly reduced, and the welding effect is better especially in the aspects of aluminum welding and the like. In addition, the periphery of the keyhole is also heated, so that the molten metal vapor in the welding molten metal is not solidified before being discharged, thereby greatly reducing the internal air holes and realizing high-quality welding.

However, the reflectivity of the copper material to near infrared light is as high as 95%, so that the dual-core fiber laser based on near infrared light has low power density in a heating area around the keyhole, and is almost totally reflected by the surface of the copper material, so that insufficient heating is caused, and the purposes of reducing splashing and air holes cannot be well realized.

Disclosure of Invention

In view of the above, the present invention provides a laser light source that can greatly improve the light condensing property and the laser output while solving the above-mentioned problems.

In order to solve the above-mentioned problems, the present invention provides a laser light source comprising a plurality of LD modules, wherein the plurality of LD modules and a plurality of collimating lenses for collimating light emitted from the LD modules are arranged in a matrix in a container, and in the matrix array, a X, Y, Z axis orthogonal to each other is provided, the direction of the emitted light is a Z axis, the light emitted from the LD modules, the propagation axis with a large divergence angle is a FAST axis, the propagation axis with a small divergence angle is a SLOW axis, the distance between the mirrors of the stacked mirrors stacked in the SLOW axis direction is minimized by oblique reflection in the SLOW axis direction of the collimated light emitted from the LD modules, a dense stacked light beam with almost no gap in the Z axis direction is obtained, immediately before the stacked light beam is incident on the condenser lens, a SLOW axis or a FAST axis is provided near the condenser lens, or a plurality of wedge prism plates with optical axes being independently inclined are provided, the wedge prism plates with a small divergence angle are adjusted, the stacked light beam is made to be placed near the same axis or the same, and the wedge prism plates are placed near the condenser lens, and the wedge prism plates are placed near the tilt axis.

A cylindrical lens having a curvature in a SLOW axis or FAST axis direction of an LD is provided before incidence of a condenser lens to reduce the size of an imaging spot in the SLOW axis direction or FAST axis direction.

A cylindrical lens having curvature in each axial direction is added in the direction of the SLOW axis or FAST axis of the outgoing light of the LD module, the imaging points dispersed by the cylindrical lens are condensed into one by the beam angle tilting function based on the wedge prism plate, and a wedge prism plate corresponding to the cylindrical lens is installed in the direction of the SLOW axis or FAST axis corresponding to the cylindrical lens, which is located just before the condensing lens, for forming the scattering image point of each LD element.

The cylindrical lens has curvature in the SLOW axis or FAST axis direction and is away from the condenser lens, not only reducing the spot size, but also reducing the beam divergence angle in the SLOW axis direction, increasing the luminous flux incident into the effective diameter of the condenser lens.

The total laminated beam size incident on the condenser lens is reduced, the central axis of the cylindrical lens is eccentric with respect to the optical axes of the plurality of laminated beams from two or more LD modules, and the plurality of laminated beams are brought into contact with each other or brought close to each other or overlapped with each other by adjusting the amount of the eccentricity.

By disposing a plurality of wedge prism plates having wedge prism angles in a matrix at the outlet of the LD modules, a collimated light beam composed of a plurality of 1-column laminated light beams, in which a plurality of LD modules are laminated in the SLOW axis direction, is focused on one point by a condenser lens, thereby fine-tuning the condensing position.

An independent cylindrical lens with radian is added at the outlet of the LD module, and the condensing size of the condensing lens is larger than the light emitted by the LD module, so that the condensing size is reduced.

A plurality of collimated light beams composed of a plurality of 1-row laminated light beams laminated in the SLOW axis direction from a plurality of LD modules are condensed in the SLOW axis direction by a cylindrical lens to form a plurality of reduced light beams, and before the plurality of reduced light beams are incident on a condensing lens, the angle of a wedge prism is individually changed corresponding to each row of laminated light beams, so that the outgoing light of LD elements of the LD modules is condensed at one point.

The invention has the beneficial effects that: the invention can greatly improve the light focusing property and the laser output by adding the wedge prism plate right in front of the condensing lens after the cylindrical lens. By adding a wedge prism plate immediately before the condensing lens after the cylindrical lens, the condensing property and the laser output can be greatly improved. By adding a wedge-shaped prism plate in front of the condensing lens behind the cylindrical lens, both condensing and laser power are obviously improved.

Drawings

Fig. 1 is a basic configuration diagram of a laser light source that outputs a laminated collimated light beam according to a first embodiment, fig. 1 (a) is a plan view, fig. 1 (b) is a side view, and fig. 1 (c) is a rear view.

Fig. 2 is an internal configuration diagram of the condensing optical system 208, fig. 2 (a) is a plan view, and fig. 2 (b) is a side view.

Fig. 3 shows a schematic view of a state in which a parallel light beam 300 is condensed by a condenser lens 301 and imaged on a focal point 302.

Fig. 4 is an overall configuration diagram of the laser light source in the case where the cylindrical lens+wedge prism plate is attached only in the SLOW axis direction, and fig. 4 (a) is a plan view, fig. 4 (b) is a side view of fig. 4 (a), and fig. 4 (c) to 4 (e) are converging points of the core end face 26 of the optical fiber 25.

Fig. 5 is an overall configuration diagram of a laser light source to which a cylindrical lens and a wedge prism plate are attached only in the fast axis direction, fig. 5 (a) is a plan view, fig. 5 (b) is a side view of fig. 5 (a), and fig. 5 (c) to 5 (e) are converging points incident on the core end face 26 of the optical fiber 25.

Fig. 6 is an overall configuration diagram of the laser light source in the case where a cylindrical lens+wedge prism plate is added to the slow axis and the fast axis, fig. 6 (a) is a plan view, fig. 6 (b) is a side view of fig. 6 (a), and fig. 6 (c) is a converging point of the core end face 26 incident on the optical fiber 25.

Fig. 7 compresses the light beams of the fast axis of the two LD modules 201, 202 and connects them to the condensing optical axis 700. The beam is made to enter a top view of the laser light source in the effective diameter stop 701 in the fast axis direction.

Fig. 8 is a top view of an embodiment in which fast axis beams of two LD modules 201, 202 are condensed by a cylindrical lens 800, and the respective beams are changed so that the wedge prism angle is changed to image.

Detailed Description

The following examples are further illustrative and supplementary of the present invention and are not intended to limit the invention in any way. The technical scheme of the invention is described in detail below with reference to the accompanying drawings:

[ example 1]

Fig. 1 is a basic configuration diagram of a laser light source that outputs a laminated collimated light beam according to a first embodiment, fig. 1 (a) is a plan view, fig. 1 is a side view, and fig. 1 (c) is a rear view.

The laser beam 203 in the Z direction emitted from the two laser modules 201 and 202 is reflected in the-X direction by the lamination mirror 21, and becomes laminated beams 104 and 204 laminated in the SLOW axis direction. The laminated beams 104 and 204 are further reflected by FAST axis mirrors 205 and 206 in the Y direction so that they are also superimposed in the FAST axis direction as a parallel laminated beam 207 superimposed on the FAST axis and SLOW axis.

Fig. 2 is an internal configuration diagram of the condensing optical system 208, fig. 2 (a) is a plan view, and fig. 2 (b) is a side view. Laminated beam 207 is focused by cylindrical lens 208 having a curvature in the SLOW axis direction to become condensed beam 209.

The condensed light beam 209 is compressed in the FAST axis direction by two triangular prisms 210, and enters wedge prism plates 211 and 212 to move the optical axis in the SLOW axis direction. Becomes a compressed parallel beam 213 parallel to the SLOW axis direction. The compressed parallel light beam 213 is condensed by the condensing lens 24 and is radiated to the end face 26 of the optical fiber, and the compressed parallel light beam 213 compressed by the condensing optical system of fig. 2 is within the effective diameter of the condensing lens 24, and the focal point size can be further reduced so as to be incident on the core of the end face 26 of the optical fiber.

Fig. 3 (a) shows a state in which a parallel light flux 300 is condensed by a condenser lens 301 and imaged on a focal point 302. Fig. 3 (b) shows a cylindrical lens 303 having curvature in the x direction for the parallel light beam 300, and the x-direction focused light beam 304 is made incident on the condenser lens 301 in such a manner that the x-direction beam width becomes smaller when moving in the f direction. Then, an image is formed at a position of a short focal length in the-f direction. The focal length of the focal point 305 becomes smaller when the cylindrical lens 303 is added according to the characteristics of a convex lens having a smaller condensing size as the focal length becomes shorter. In the state of fig. 3b, wedge prism plates 306 (not shown) and 307, which linearly thicken in the x and-x directions symmetrically with respect to the optical axis 305, are arranged at positions directly in front of the incident light of the condenser lens 301. The wedge prism angle θ of the wedge prism plates 306, 307 is adjusted to return the x-direction focused beam 304 to a parallel state. Therefore, the light beam incident on the condenser lens 301 is further changed into a collimated light beam 308 after reduction. The focal length of the focal point 309 focused by the condenser lens 301 is the same as that of fig. 3 (a), but the focal length size is reduced.

For convenience of explanation, the case where the outermost light beam 310 is corrected in parallel is described, but in reality, the light beam 308 is not completely parallel due to spherical aberration of the condenser lens 301 and the cylindrical lens 303. Only the angle θ of the wedge prism plate 307 is adjusted to focus the light on the focus of the condenser lens. Further, since the wedge angle θ of the wedge prism plate 307 moves only the outermost light beam 310 toward the focal point, the wedge angle θ to be focused also changes as the distance of the optical axis changes. In practical applications, since the FAST axis and SLOW axis beams of the LD element 12 have astigmatism differences, the focus of the condenser lens 301 in the FAST axis direction and the focus in the SLOW direction are shifted, and since the diffusion angle of the LD element itself is also shifted, it is necessary to individually correct the wedge prism angle for each of the 12 LD elements to accurately focus the light. Therefore, in practical application, the focal length is precisely adjusted by adjusting the wedge prism angle θ of the wedge prism plate 900 at the exit of the LD module 11 shown in fig. 1 and the cylindrical lens of the cylindrical lens 901, so that the size of the spot incident on the core of the fiber end face 26 can be adjusted. The precise focus adjustment method is to measure the alignment accuracy and beam characteristics of 12 LD elements in advance and then adjust the wedge prism angle θ and focal length of the cylindrical lens 901 of one or several LD elements. Specifically, the various optical elements are pre-cut into rectangles and then assembled together in a tiled fashion while checking on the display whether they are in the focus position.

[ Example 2]

The laminated light flux 104 laminated in the SLOW axis direction from the LD module 201 in the laminated mirror 21 in fig. 1 is reflected in the y direction by the mirror 205, and becomes the condensed light flux 400 condensed in the SLOW axis by the cylindrical lens 23 having a curvature in the SLOW axis direction.

The focused light beam 400 is a parallel light beam 402, and the wedge prism plate 401 in the slow axis direction has a wedge prism angle θ, and the light beam is condensed by the condenser lens 24 and then enters the optical fiber 25. Since the optical fiber 25 has an incident angle, when the incident angle of the optical fiber 25 exceeds NA, the optical fiber 25 is thermally damaged, and thus, the light beam exceeding the NA of the optical fiber is removed in the diaphragm 403. Since the light beam in the SLOW axis direction is reduced by the condensing action of the cylindrical lens 23, the output loss 404 due to the diaphragm 403 can be eliminated in the SLOW axis direction, and the output can be increased.

Next, the effect of reducing the converging point of the core end surface 26 of the optical fiber 25 will be described with reference to fig. 4 (c) to 4 (e).

Fig. 4 (c) shows an imaging point 404 in the case where the wedge prism plate 401 is not used for the cylindrical lens 23 in the SLOW axis direction, and the imaging point extends from the optical fiber core end face 26 in both the FAST axis direction and the SLOW axis direction.

In fig. 4 (d), by adding the cylindrical lens 23, light is condensed in the SLOW axis direction, and the imaging points 405 are dispersed into three, and further enlarged so as to protrude further from the end face 26.

Fig. 4 (e) shows a wedge prism plate 401 further added to move the dispersed imaging dots 405, and finally forming imaging dots 406 with smaller size in the SLOW direction.

[ Example 3]

Fig. 5 is an overall configuration diagram of a laser light source in which a cylindrical lens and a wedge prism plate are attached in the fast axis direction, fig. 5 (a) is a plan view, fig. 5 (b) is a side view of fig. 5 (a), and fig. 5 (c) to 5 (e) are converging points of the core end face 26 incident on the optical fiber 25.

According to the laminated reflecting mirror 21 in fig. 1, the laminated light beam 104 emitted from the LD module 201 and laminated in the SLOW axis direction is condensed in the FAST axis direction by the cylindrical lens 55 having a curvature in the FAST axis direction, and the light beam is further reflected by the reflecting mirror 205 in the Y direction, forming the FAST axis condensed light beam 500.

The condensed light beam 500 is formed into a parallel light beam 502 by the action of a slow-axis wedge prism plate 501 having a wedge prism angle η in the fast axis direction, and is condensed by the condensing lens 24, and then enters the optical fiber 25.

Since the Fast axis beam is reduced by the Fast axis cylindrical lens 55, the disturbance loss 504 due to the Fast axis grating 403 can be eliminated, and the output can be increased.

Next, the effect of narrowing the condensed point incident on the core end face 26 of the optical fiber 25 will be described with reference to fig. 4C to 4E.

Fig. 5 (c) is a cylindrical lens 55 in the fast axis direction and an imaging point 404 in the case where the wedge prism plate 501 is not present. Extending from the fiber core end face 26 in both the fast axis direction and the slow axis direction.

Fig. 5 (d) is a view of focusing light in the fast axis direction by adding a fast axis cylindrical lens 55. But the imaging point 505 splits into two in the fast axis direction and extends outwardly from the end face 26.

Fig. 5 (e) can superimpose the imaging point 505 separated into two on one by adding the wedge prism plate 501. The light flux in the fast axis direction becomes an imaging point 506 that becomes smaller within the width of the end face 26.

[ Example 4]

The laminated beam 104 laminated in the slow axis direction is condensed in the fast axis direction by the cylindrical lens 55 having a curvature in the fast axis direction, and is reflected in the y direction by the mirror 205 to become the fast axis condensed beam 500.

The light beam 500 passes through a cylindrical lens 23 having a curvature in the slow axis direction, and becomes a biaxial condensed light beam 600 condensed in the slow direction as well.

The biaxial condensed light beam 600 is formed into a parallel light beam 601 having parallel biaxial directions in the slow axis wedge prism plate 401 and the fast axis wedge prism 501, condensed by the condenser lens 24, and then enters the optical fiber 25. The cylindrical lenses 23, 55 and the wedge prism plates 401, 501 of both the Slow axis and the fast axis can increase the output since both axes can be free from interference of the aperture 403.

Next, the effect of narrowing the condensed point incident on the core end face 26 of the optical fiber 25 will be described with reference to fig. 6 (c).

Fig. 6 (c) is an imaging point 404 in the case where both axes have no cylindrical lenses 23, 55 and no wedge prism plates 401, 501. Both axes extend from the fiber core end face 26.

Both axes have imaging points 602 in the case of cylindrical lenses 23, 55 and wedge prism plates 401, 501. Since it is reduced in both axes, the full beam can be incident into the fiber core end face 26.

[ Example 5]

Fig. 7 shows the compression of the fast axis beam of the two LD modules 201, 202 and the connection of the fast axis beam to the condensing optical axis 700. The beam is made to enter a top view of the laser light source in the effective diameter stop 701 in the fast axis direction.

The stacked light fluxes 104 and 204 stacked in the slow axis direction pass through cylindrical lenses 702 and 703 having curvature in the fast axis direction, are condensed in the fast axis direction, and are reflected in the y direction by 45 ° mirrors 205 and 206, thereby forming fast axis condensed light flux 704.

The fast axis condensed light beam 704 is not disturbed by the diaphragm 701, but is formed into a light beam 707 parallel to the fast axis direction by wedge prism plates 705 and 706 having a predetermined angle epsilon, and is condensed by the condenser lens 24, and then enters the optical fiber 25. In this configuration, by decentering the cylindrical lenses 702 and 703 having curvature in the fast axis direction, it is possible to bring fast axis direction condensed light beams of the two LD modules 201 and 202 which are not originally in contact with the fast axis direction condensed light into contact with each other or into close proximity or interference with each other, and then to perform angle correction by the wedge prism and make the incident light beam enter the optical fiber 25.

In fig. 7, by decentering the cylindrical lens 702 to the left and aligning the central axis of the cylindrical lens 702 with the leftmost position of the LD module 201, the 45 ° incident mirror 205 can be reflected by 45 ° and aligned with the condensing optical axis 700.

Likewise, by decentering the cylindrical lens 703 to the right, aligning the central axis of the cylindrical lens 703 with the rightmost position of the LD module 202, the cylindrical lens can reflect 45 degrees by a 45-degree mirror and align with the condensing optical axis 700.

According to the above configuration, since the light flux incident on the condenser lens can be reduced, the condenser lens having a short focal length can be used to improve the condensing performance and reduce the condensing size in the fast direction of the cylindrical lenses 702 and 703.

In addition, in the above-described embodiment 2, by adding a cylindrical lens and a wedge prism plate in the Slow axis direction, light can be focused in the Slow axis direction as well.

There are each column of light beams (1) to (4) in the laminated light beams 104, 204 laminated in the slow axis direction. The light fluxes (1) to (4) are condensed in the fast axis direction by the cylindrical lens 800 having curvature, and are reflected in the y direction by the 45-degree mirror 801, becoming multiple light fluxes 804 condensed in the fast axis direction.

The light fluxes (1) to (4) constituting the multiple light flux 804 adjust wedge prism angles of the four wedge prism plates 806 to 809 in parallel to the condensing optical axis 805. Thus, parallel multiple light beams 810 are obtained. Since the parallel multiple light beam 810 is parallel to the condenser lens 24, it is focused at the focal length position of the core end face 26 of the optical fiber 25.

It should be noted that instead of providing a 45 degree mirror, the multiple beam 804 may be made to directly strike the wedge prism plates 806-809 and be imaged onto the optical fiber 25 according to the same principle.

In fig. 8, gaps D1, D2, and D3 are provided between the light fluxes (1) to (4) of the respective columns of the laminated light fluxes 104 and 204.

However, even without gaps D1, D2, D3, the wedge prism angles of the four wedge prisms can be adjusted and imaged on the end face of the optical fiber 25.

Although the present invention has been disclosed by the above embodiments, the scope of the present invention is not limited thereto, and each of the above components may be replaced with similar or equivalent elements known to those skilled in the art without departing from the spirit of the present invention.

Claims

1. A laser light source comprising a plurality of LD modules, wherein the plurality of LD modules and a plurality of collimating lenses for collimating light emitted from the LD modules are arranged in a matrix in a container, a X, Y, Z axis orthogonal to each other is provided in the matrix array, the direction of the emitted light is a Z axis, a propagation axis of light emitted from the LD modules is a FAST axis, a propagation axis of light having a small divergence angle is a SLOW axis, the distance between each reflecting mirror of a stacked mirror stacked in the SLOW axis direction is minimized by oblique reflection in the SLOW axis X axis direction of the collimated light emitted from the LD modules in the Z axis direction, a dense stacked light beam having a Z axis direction of near zero gap is obtained, the SLOW axis or the FAST axis is disposed in the vicinity of a condenser lens immediately before the stacked light beam is incident on the condenser lens, the light beam is focused on the same position via a lens by adjusting a wedge prism angle of a plurality of wedge prism plates, the plurality of prism plates are disposed in the vicinity of the wedge prism plates, the SLOW axis or the FAST axis is disposed in the vicinity of the wedge prism plates, and the FAST axis is tilted in front of the FAST axis;

a cylindrical lens having a curvature in a SLOW axis or FAST axis direction of the LD is provided before incidence of the condenser lens to reduce a size of an imaging spot in the SLOW axis direction or FAST axis direction;

2. The laser light source according to claim 1, wherein a cylindrical lens having curvature in each axial direction is added in a direction of a SLOW axis or a FAST axis of the outgoing light of the LD module, imaging points dispersed by the cylindrical lens are condensed into one by a beam angle tilting function based on the wedge prism plate, and a wedge prism plate corresponding to the cylindrical lens is installed in a direction of the SLOW axis or the FAST axis corresponding to the cylindrical lens, the wedge prism plate being located just before the condensing lens for forming a scattering image of each LD element.

3. The laser light source according to claim 2, wherein the cylindrical lens has a curvature in a SLOW axis or FAST axis direction and is distant from the condenser lens, not only reducing a spot size but also reducing a beam divergence angle in the SLOW axis direction, so that a beam incident into an effective diameter of the condenser lens increases.

4. The laser light source according to claim 1, wherein the condensed position is finely adjusted by focusing a collimated light beam composed of a plurality of 1-column stacked light beams, which are stacked in the SLOW axis direction, at one point by a condensing lens by disposing a plurality of wedge prism plates having wedge prism angles in a matrix at the outlets of the LD modules.

5. The laser light source as claimed in claim 4, wherein a separate cylindrical lens having a curvature is added at an outlet of the LD module, and a condensing size of the condensing lens is larger than that of the light emitted from the LD module for reducing the condensing size.

6. The laser light source according to claim 5, wherein the collimated light beam composed of a plurality of 1-row laminated light beams laminated in the SLOW axis direction from the plurality of LD modules is condensed in the SLOW axis direction by the cylindrical lens to form a multiple reduced light beam, and the wedge prism angle is individually changed in correspondence with each row of laminated light beams before the multiple reduced light beam is incident on the condenser lens, so that the outgoing light of the LD element of the LD module is condensed at one point.