CN114247988A

CN114247988A - Laser light source

Info

Publication number: CN114247988A
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: 2022-03-29
Anticipated expiration: 2040-09-23
Also published as: CN114247988B

Abstract

The laser light source of the present invention comprises a plurality of LD modules arranged in a matrix in a container, a plurality of collimating lenses for collimating light emitted from the LD modules, X, Y, Z axes orthogonal to each other being provided in the matrix array, a dense laminated beam having almost no gap in the Z-axis direction being obtained by obliquely reflecting a SLOW axis of collimated light emitted from the LD modules in the Z-axis direction toward the X-axis direction so that the pitch of respective mirrors of the stacked mirrors stacked in the SLOW axis direction is minimized to minimize the gap of a collimated beam group in the Z-axis direction, the laminated beam being focused at the same position via a condensing lens by adjusting the wedge prism angles of a plurality of wedge prism plates provided in the vicinity of the condensing lens immediately before the laminated beam is incident on the condensing lens, the invention can greatly improve the light-gathering property and the laser output by inclining the optical axis to the SLOW axis or the FAST axis.

Description

Laser light source

[ technical field ] A method for producing a semiconductor device

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

[ background of the invention ]

In recent years, as a method for reducing the occurrence of spatter, blowholes, and the like during laser welding, there has been an important research direction, and the application of a conventional near-infrared dual-fiber laser is becoming wider, and the dual-fiber laser includes a high-brightness central beam that can rapidly generate a keyhole and a low-brightness annular beam that can heat a region around the keyhole, so that hybrid welding of keyhole welding and thermal conduction welding can be performed at the same time. The mixed welding process heats 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, metal vapor is smoothly discharged, splashing can be greatly reduced, and the welding effect is better particularly in the aspects of aluminum welding and the like. Moreover, since the periphery of the keyhole is also heated, the molten pool is not solidified before the metal vapor in the molten metal is discharged, so that the internal porosity can be greatly reduced, and high-quality welding can be realized.

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

[ summary of the invention ]

In view of the above, the present invention provides a laser light source that can solve the above-mentioned problems and can significantly improve the light condensing performance and the laser output.

In order to solve the above-described problems, the present invention provides a laser light source including a plurality of LD modules, the plurality of LD modules and a plurality of collimating lenses for collimating light emitted from the LD modules being arranged in a matrix in a container, X, Y, Z axes orthogonal to each other are provided in the matrix array, a direction of outgoing light is a Z axis, light emitted from the LD modules, a propagation axis having a large divergence angle is a FAST axis, a propagation axis having a small divergence angle is a SLOW axis, by obliquely reflecting a SLOW axis of collimated light emitted from the LD modules in the Z axis direction toward the X axis direction, a pitch of respective mirrors of a stack mirror stacked in the SLOW axis direction is made to minimize a gap of a collimated light beam group in the Z axis direction to obtain a dense stacked light beam having almost no gap in the Z axis direction, the SLOW axis or the FAST axis is provided in the vicinity of the condensing lenses immediately before the stacked light beam is incident on the condensing lenses, or a plurality of wedge prism plates whose two axes independently tilt the optical axis, the stacked light beams are focused on the same position via a condensing lens by adjusting the wedge prism angles of the plurality of wedge prism plates, the plurality of wedge prism plates are disposed near the condensing lens, and the light beams of the SLOW axis or the FAST axis are tilted before the stacked light beams are injected into the condensing lens, or the stacked light beams are independently tilted on the two axes.

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 the size of an imaging spot in the SLOW axis or FAST axis direction.

And a cylindrical lens with curvature in each axis direction is added in the direction of a SLOW axis or a FAST axis of emergent light of the LD module, dispersed imaging points of the cylindrical lens are condensed into one by a light beam angle inclination function based on the wedge prism plate, and the wedge prism plate corresponding to the cylindrical lens is installed in the direction of the SLOW axis or the FAST axis corresponding to the cylindrical lens and is just positioned in front of the condensing lens to form scattering image forming points of each LD element.

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

The size of the total laminated light flux entering 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 light fluxes from two or more LD modules, and the plurality of laminated light fluxes are brought into contact with each other, brought into proximity to each other, or overlapped with each other by adjusting the amount of eccentricity.

By arranging a plurality of wedge prism plates having a wedge prism angle in a matrix at the exit of the LD module, collimated light beams composed of a plurality of 1-column laminated light beams laminated in the SLOW axis direction by the plurality of LD modules are focused at one point by a condensing lens, thereby finely adjusting the condensing position.

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

Collimated beams composed of a plurality of 1-row laminated beams laminated in the SLOW axis direction from the plurality of LD modules are condensed by cylindrical lenses in the SLOW axis direction to form multiple reduced beams, and before the multiple reduced beams enter the condensing lenses, the wedge prism angle is individually changed for each row of laminated beams, so that the light emitted from the LD elements of the LD modules is condensed at one point.

The invention has the beneficial effects that: the invention adds the wedge prism plate right in front of the condenser lens after the cylindrical lens, thereby greatly improving the condensing performance and the laser output at the same time. By adding a wedge prism plate immediately before the condenser lens after the cylindrical lens, the condensing performance and the laser output can be greatly improved. The wedge prism plate is added in front of the condenser lens behind the cylindrical lens, so that the condensing and laser power are obviously improved.

[ description of the 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, where fig. 1(a) is a top 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 is a schematic view showing a state where a parallel light flux 300 is condensed by a condenser lens 301 and is focused on a focal point 302.

Fig. 4 is an overall configuration diagram of a laser light source in a case where a cylindrical lens + a wedge prism plate are attached only in the SLOW axis direction, 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 light converging points incident on the core end face 26 of the optical fiber 25.

Fig. 5 is a general configuration diagram of a laser light source in 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 focused spots incident on the core end surface 26 of the optical fiber 25.

Fig. 6 is a diagram showing the overall configuration of the laser light source in the case where the 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 light converging point incident on the core end surface 26 of the optical fiber 25.

Fig. 7 compresses the fast-axis light fluxes of the two

LD modules

201 and 202 and makes them meet the condensing optical axis 700. A top view of the laser light source that causes the light beam to enter the effective diameter stop 701 in the fast axis direction.

Fig. 8 is a plan view of an embodiment in which fast-axis light beams of two

LD modules

201 and 202 are condensed by a cylindrical lens 800, and the wedge angle is changed by changing each light beam to form an image.

[ detailed description ] embodiments

The following examples are further illustrative and supplementary to the present invention and do not limit the present invention in any way. The technical scheme of the invention is described in detail in the following with reference to the attached 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, where fig. 1(a) is a top 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 stack mirror 21, and becomes the

stack beams

104 and 204 stacked 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 to become 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. The laminated beam 207 is focused by a cylindrical lens 208 having a curvature in the SLOW axis direction to become a condensed beam 209.

The condensed light 209 is compressed in the FAST axis direction by two triangular prisms 210, enters

wedge prism plates

211 and 212, and moves the optical axis in the SLOW axis direction. The compressed parallel beam 213 is parallel to the SLOW axis direction. The compressed parallel light beam 213 is condensed by the condenser lens 24 and emitted to the end surface 26 of the optical fiber, and the compressed parallel light beam 213 compressed by the condenser optical system of fig. 2 is within the effective diameter of the condenser lens 24 and can be further reduced in focal point size to be incident to the core of the end surface 26 of the optical fiber.

Fig. 3(a) shows a state where the parallel light flux 300 is condensed by the condenser lens 301 and focused on the focal point 302. Fig. 3(b) shows a cylindrical lens 303 having a curvature in the x direction with respect to the parallel light flux 300, and the focused light flux 304 in the x direction is incident on the condenser lens 301 in such a manner that the beam width in the x direction 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. When the cylindrical lens 303 is added, the focal length of the focal point 305 becomes smaller, based on the characteristic of the convex lens in which the focal length becomes shorter and the light-collecting size becomes smaller. In the state of fig. 3 b, wedge prism plates 306 (not shown) and 307 which are linearly thickened in the x and-x directions symmetrically with respect to the optical axis 305 are arranged at positions immediately before the light entrance of the condenser lens 301. The wedge angle θ of the wedge prism plates 306, 307 is adjusted to return the x-direction focused beam 304 to a collimated state. Therefore, the light flux entering the condenser lens 301 becomes a further reduced parallel light flux 308. The focal length of the focal point 309 focused by the focusing lens 301 is the same as in fig. 3(a), but the focal length size is reduced.

Note that, for convenience of explanation, the case where the outermost light flux 310 is corrected in parallel has been described, but actually, the light flux 308 is not perfectly parallel due to spherical aberration of the condenser lens 301 and the cylindrical lens 303. The angle θ of the wedge prism plate 307 is simply adjusted to focus the light on the focal point of the condenser lens. Further, since the wedge angle θ of the wedge prism plate 307 moves only the outermost light flux 310 to the focal point, the wedge angle θ to be focused changes as the distance of the optical axis changes. In addition, in practical applications, since the beams of the FAST axis and SLOW axis of the LD element 12 have an astigmatic difference, the focal point of the condenser lens 301 in the FAST axis direction and the focal point in the SLOW axis direction are shifted, and further, since the diffusion angle of the LD element itself is also shifted, it is necessary to correct the wedge prism angle individually for each of the 12 LD elements to focus the light precisely. Therefore, in practical applications, the focal length is precisely adjusted by adjusting the wedge prism angle θ of the wedge prism plate 900 and the cylindrical lens of the cylindrical lens 901 at the exit of the LD module 11 shown in fig. 1, so that the size of the light spot incident on the core of the optical 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 the focal length of the cylindrical lens 901 of one or several LD elements. Specifically, a plurality of optical elements are cut into a rectangular shape in advance and then assembled together in a tiled manner while checking whether they are in the position of the focal point on the display.

[ example 2 ]

The laminated light flux 104 laminated in the SLOW axis direction from the LD module 201 on the laminated mirror 21 in fig. 1 is reflected in the y direction by the mirror 205, and then becomes a 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 flux 400 is a parallel light flux 402, and the slow axis direction wedge prism plate 401 has a wedge prism angle θ, and the light flux is condensed by the condenser lens 24 and 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 therefore, the light flux exceeding the NA of the optical fiber is removed by the aperture 403. Since the light flux in the SLOW axis direction is reduced by the light converging 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 focal point of the light incident on 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 the image 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 extends from the optical fiber core end surface 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 surface 26.

FIG. 4(e) shows the further addition of the wedge prism plate 401 to cause the dispersed imaging spots 405 to be shifted to finally form imaging spots 406 with a smaller dimension in the SLOW direction.

[ example 3 ]

Fig. 5 is a general 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 light converging points incident on the core end surface 26 of the optical fiber 25.

According to the laminated mirror 21 in fig. 1, the laminated 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 is further reflected by the mirror 205 in the Y direction to form the FAST axis condensed beam 500.

The condensed light flux 500 becomes a parallel light flux 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 condenser lens 24 and then enters the optical fiber 25.

Since the Fast axis cylindrical lens 55 reduces the light flux in the Fast axis direction, the interference loss 504 caused by the Fast axis grating 403 can be eliminated, and the output can be increased.

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

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

In fig. 5(d), a fast axis cylindrical lens 55 is added to condense light in the fast axis direction. However, the imaging point 505 is divided into two in the fast axis direction and extends outward from the end face 26.

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

[ example 4 ]

The laminated beam 104 laminated in the slow axis direction passes through the cylindrical lens 55 having a curvature in the fast axis direction, is condensed in the fast axis direction, and is further reflected in the y direction by the mirror 205, thereby becoming a fast axis condensed beam 500.

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

The biaxial condensed light flux 600 becomes a parallel light flux 601 whose both axes are parallel in the slow axis wedge prism plate 401 and the fast axis wedge prism 501, and is 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 focal point incident on the core end surface 26 of the optical fiber 25 will be described with reference to fig. 6 (c).

Fig. 6(c) is an imaging spot 404 in the case where neither axis has the

cylindrical lenses

23, 55 and the

wedge prism plates

401, 501. Both axes extend from the fiber core end face 26.

Both axes have

cylindrical lenses

23, 55 and imaging points 602 in the case of

wedge prism plates

401, 501. Because of the demagnification in both axes, a full beam can be incident into the fiber core end face 26.

[ example 5 ]

Fig. 7 is a diagram in which the fast-axis light fluxes of the two

LD modules

201 and 202 are compressed and made to meet the condensing optical axis 700. A top view of the laser light source that causes the light beam to enter the effective diameter stop 701 in the fast axis direction.

The

laminated beams

104 and 204 laminated 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 a fast axis condensed beam 704.

The fast-axis condensed light beam 704 is not disturbed by the stop 701, but becomes a light beam 707 parallel to the fast axis direction by the

wedge prism plates

705 and 706 having a predetermined angle ∈, 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, the fast axis direction condensed light beams of the two

LD modules

201 and 202 which are not originally in contact with the condensed light in the fast axis direction can be brought into contact with each other, or brought close to or interfered with each other, and then subjected to angle correction by the wedge prism and incident on the optical fiber 25.

Fig. 7 enables the 45 ° incident mirror 205 to reflect 45 ° and align with the condensing optical axis 700 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.

Similarly, by decentering the cylindrical lens 703 to the right, the central axis of the cylindrical lens 703 is aligned with the rightmost position of the LD module 202, and the cylindrical lens can reflect 45 degrees by the 45-degree mirror and be aligned with the light-collecting optical axis 700.

According to the above configuration, since the light flux incident on the condenser lens can be reduced, the condensing performance can be improved and the condensing size in the fast direction of the

cylindrical lenses

702 and 703 can be reduced by using the condenser lens having a short focal length.

In example 2, the light can be focused in the Slow axis direction by adding a cylindrical lens and a wedge prism plate in the Slow axis direction.

Fig. 8 is a plan view of an embodiment in which fast-axis light beams of two

LD modules

Among the

laminated beams

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

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

It should be noted that instead of a 45 degree mirror, the multiple beams 804 could be made to directly enter the wedge prism plates 806-809 and imaged onto the optical fiber 25 according to the same principles.

In addition, in fig. 8, gaps D1, D2, D3 are provided between the light fluxes (1) to (4) of each column in the laminated light fluxes 104, 204.

However, even if the gaps D1, D2, and D3 are not provided, the wedge prism angles of the four wedge prisms can be adjusted to form an image on the end face of the optical fiber 25.

While the invention has been described with reference to the above embodiments, the scope of the invention is not limited thereto, and 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 invention.

Claims

1. A laser light source comprising a plurality of LD modules, the plurality of LD modules and a plurality of collimator lenses for collimating light emitted from the LD modules being arranged in a matrix in a container, wherein X, Y, Z axes orthogonal to each other are provided in the matrix array, the direction of the emitted light is a Z axis, a propagation axis in which the divergence angle of light emitted from the LD modules is large is a FAST axis, and a propagation axis in which the divergence angle is small is a SLOW axis, and wherein by obliquely reflecting a SLOW axis of collimated light emitted from the LD modules in a Z axis direction toward an X axis direction, the pitch of respective mirrors of a stack mirror stacked in the SLOW axis direction is made to be the smallest in the gap of a group of collimated light beams in the Z axis direction, to obtain a dense stacked light beam in which the Z axis direction is a near-zero gap, the FASOW axis or the FAST axis being disposed in the vicinity of a condenser lens immediately before the stacked light beam is incident on the condenser lens, the stacked light beams are focused on the same position through a condensing lens by adjusting the wedge prism angles of a plurality of wedge prism plates provided near the condensing lens, and the light beams of the SLOW axis or the FAST axis are tilted or independently tilted on the SLOW axis and the FAST axis before the stacked light beams enter the condensing lens.

2. The laser light source according to claim 1, wherein a cylindrical lens having a curvature in a SLOW axis direction or a 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 the FAST axis direction.

3. The laser beam source of claim 2, wherein a cylindrical lens having a curvature in each axis direction is added in the direction of the SLOW axis or FAST axis of the outgoing light from the LD module, the dispersed imaging points of 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 the direction of the SLOW axis or FAST axis corresponding to the cylindrical lens, the wedge prism plate being located just before the condensing lens for forming the scattering image of each LD element into one point.

4. The laser light source of claim 3, wherein the cylindrical lens has curvature in a direction of a SLOW axis or a FAST axis and is away from the condenser lens to reduce not only a spot size but also a beam divergence angle in the direction of the SLOW axis to increase a beam incident into an effective diameter of the condenser lens.

5. The laser light source according to any one of claims 1 to 4, wherein the size of the entire laminated beam incident on the condenser lens is made small, the central axis of the cylindrical lens is made 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 eccentricity.

6. The laser light source according to claim 5, wherein the fine adjustment of the condensing position is performed by focusing a collimated light beam composed of a plurality of 1-column laminated light beams, which are laminated in the SLOW axis direction by a plurality of LD modules, at one point by arranging a plurality of wedge prism plates having a wedge prism angle in a matrix manner at the exit of the LD modules.

7. The laser light source of claim 6, wherein a separate cylindrical lens having an arc is added at the exit of the LD module, and the condensing lens has a condensing size larger than the light emitted from the LD module for reducing the condensing size.

8. The laser beam source of claim 7, wherein a collimated beam composed of a plurality of 1-row laminated beams laminated in the SLOW axis direction from a plurality of the LD modules is condensed by a cylindrical lens in the SLOW axis direction to form a multiple-reduced beam, and before the multiple-reduced beam is incident on the condensing lens, the wedge prism angle is individually changed corresponding to each row of the laminated beams to condense the outgoing light from the LD elements of the LD modules at one point.