JP7585987B2 - Light source device, processing device, and inspection method - Google Patents

Description

The present invention relates to a light source device, a processing device, and an inspection method.

Light source devices that focus the laser light emitted from multiple laser diodes and input it into an optical fiber are used in laser processing and other applications. The more laser diodes used, the higher the output that can be achieved, but the focused laser light must be coupled to the core end face of the optical fiber, requiring precise position adjustment of each optical system.

For example, Patent Document 1 discloses a light source device in which the laser light emitted from multiple laser diodes is collimated and introduced into an anamorphic optical element, the diameter in the fast axis direction is reduced, and then the light is input into an optical fiber, which is then combined into a single beam and output.

JP 2005-114977 A

According to the technology of Patent Document 1, the beam diameter in the fast axis direction is reduced, which may facilitate coupling of the laser light to the core end face of the optical fiber. However, when each optical system is fixed by welding or adhesive, a slight positional shift occurs in the laser light compared to before fixing, and the laser light may not be properly coupled. In this case, a problem may arise in that it is not easy to correct the physical quantity related to the output from the optical fiber (for example, the output power of the laser light) as was previously possible.

This disclosure has been made to solve these problems, and its purpose is to provide a technology that can easily correct physical quantities related to the output from an optical fiber.

The light source device of the present disclosure includes a plurality of light sources, a plurality of collimating optical systems, a beam diameter adjustment optical system, a focusing optical system, an optical fiber, and a wedge plate. The plurality of light sources output laser light. The plurality of collimating optical systems collimate the laser light output from the plurality of light sources. The beam diameter adjustment optical system reduces the beam diameter in the fast axis direction of each of the laser light that has passed through the plurality of collimating optical systems, or expands the beam diameter in the slow axis direction of each of the laser light. The focusing optical system focuses the laser light that has passed through the beam diameter adjustment optical system. The laser light focused by the focusing optical system is input to the optical fiber. The wedge plate is arranged in a rotatable manner within a plane perpendicular to the optical axis direction of the laser light that has passed through the plurality of collimating optical systems. The wedge plate has an entrance surface and/or an exit surface that has a non-perpendicular angle with respect to the optical axis direction.

The inspection method of the present disclosure is a method for inspecting a light source device. The light source device includes a plurality of light sources, a plurality of collimating optical systems, a beam diameter adjustment optical system, a focusing optical system, and an optical fiber. The plurality of light sources output laser light. The plurality of collimating optical systems collimate the laser light output from the plurality of light sources. The beam diameter adjustment optical system reduces the beam diameter in the fast axis direction of each of the laser light that has passed through the plurality of collimating optical systems, or expands the beam diameter in the slow axis direction of each of the laser light. The focusing optical system focuses the laser light that has passed through the beam diameter adjustment optical system. The laser light focused by the focusing optical system is input to the optical fiber. The inspection method includes disposing a wedge plate in a rotatable manner within a plane perpendicular to the optical axis direction of the laser light that has passed through the plurality of collimating optical systems. The wedge plate has an entrance surface and/or an exit surface that has a non-perpendicular angle with respect to the optical axis direction. The inspection method further includes rotating the wedge plate to set a physical quantity related to the output of the optical fiber to a threshold value or more.

According to the present invention, the wedge plate can be rotated by an inspector or the like to displace the focusing position on the incident surface of the optical fiber in the fast axis direction. As a result, the light source device can easily correct the physical quantity related to the output from the optical fiber.

1 is a functional block diagram of a processing device to which a light source device according to an embodiment of the present invention is applied; FIG. 2 is a diagram illustrating an example of the configuration of a light source device. FIG. 2 is a diagram illustrating an example of the configuration of a light source device. FIG. 2 is a diagram illustrating an example of the configuration of a light source. 13 is a plan view of the wedge plate viewed from the upstream side in the Z-axis direction. FIG. FIG. 4 is a plan view of the wedge plate as viewed from the slow axis direction. 13 is a diagram showing the relationship between the amount of deviation of the light collection position on the entrance surface from the design position and the rate of change in output. FIG. 13 is a diagram showing the movement of the focusing position by rotating the wedge plate. 13 is a diagram showing the relationship between the wedge angle and the maximum displacement of the light collection position on the entrance surface when the wedge plate is rotated. FIG. FIG. 1 is a diagram showing an example of a procedure of an inspection method. FIG. 13 is a diagram illustrating an example of the configuration of a light source device according to a second embodiment. FIG. 2 is a functional block diagram of the projector.

The following describes in detail an embodiment of the present invention with reference to the drawings. Note that the same or corresponding parts in the drawings are given the same reference numerals and their description will not be repeated.

First Embodiment
[Example of processing device configuration]
FIG. 1 is a functional block diagram of a processing device to which a light source device according to the present embodiment is applied. The processing device 10 processes a workpiece W (object to be processed) by irradiating the workpiece W with laser light. The processing is, for example, welding or cutting. The processing device 10 includes M (M is an integer of 1 or more) light source devices (light source devices 1001, . . . , 100M) and a processing head 130. The processing head 130 emits laser light output from the M light source devices toward the workpiece W. The processing head 130 has, for example, a focusing optical system that focuses the laser light output from the M light source devices. Hereinafter, one light source device is also referred to as a "light source device 100".

[Example of configuration of light source device]
2 and 3 are diagrams showing an example of the configuration of the light source device 100. Fig. 2 is a diagram showing the arrangement of each part of the light source device 100 in a plane including the fast axis and z axis of the laser light. The upper diagram of Fig. 3 shows the light source device 100 in a plane including the fast axis and z axis of the laser light, similar to Fig. 2, and the lower diagram of Fig. 3 shows the light source device 100 in a plane including the slow axis and z axis of the laser light.

2 and 3, the left side is also referred to as the "upstream side (or left side) of the light source device 100 in the optical axis direction," and the right side is also referred to as the "downstream side (or right side) of the light source device 100 in the optical axis direction." In the following, various optical systems are described, and the optical systems may be composed of one lens, two or more lenses, or may include components other than lenses. In addition, the upstream side of the light source device 100 in the optical axis direction may be simply referred to as the "upstream side," and the downstream side of the light source device 100 in the optical axis direction may be simply referred to as the "downstream side." In FIG. 2 and FIG. 3, the fast axis direction of the laser light (hereinafter also referred to as "parallel light") collimated by the collimating optical system 3 described later is the vertical axis direction. In addition, in FIG. 2 and FIG. 3, the slow axis direction of the collimated laser light is the depth direction, and the optical axis direction of the collimated laser light is the Z axis direction.

As shown in FIG. 2, the light source device 100 includes N light sources 2, N collimating optical systems 3, a reduction optical system 4, a focusing optical system 5, and an optical fiber 6, which are arranged in this order from the upstream side to the downstream side in the optical axis direction. N is an integer equal to or greater than 1. In the example of FIG. 2 and FIG. 3, N=3. In the example of FIG. 2 and FIG. 3, three light sources 2 are arranged in the fast axis direction. One light source 2 is arranged in the slow axis direction. Note that multiple light sources 2 may be arranged in the slow axis direction. The reduction optical system 4 corresponds to the "beam diameter adjustment optical system" of this disclosure.

The N light sources 2 each output N laser beams. The N collimating optical systems 3 are arranged in the optical paths of the laser beams from the N light sources 2, i.e., on the optical axes of the N lasers, corresponding to each of them. Each collimating optical system 3 is arranged at a position where the optical axis from the light source 2 passes through the center of the collimating optical system 3 (the center of the collimating lens that constitutes the collimating optical system 3). Hereinafter, the optical path between the light source 2 and the collimating optical system 3 is also referred to as the "optical path LD". In the example of FIG. 2, there are N optical paths L.

Each collimating optical system 3 has an incident surface 311 on which the laser light LB is incident, and an exit surface 312 from which the laser light LB is emitted. The incident surface 311 is configured as a flat surface. The exit surface 312 is configured as a curved convex surface. Note that the effective diameter of the collimating optical system 3 is preferably larger than the outer diameter of the disk-shaped portion 244.

The collimating optical system 3 collimates the laser light LB from the corresponding light source 2. Specifically, the collimating optical system 3 converts the laser light LB from the corresponding light source 2 into parallel light in both the fast axis direction and the slow axis direction. The collimating optical system 3 may be composed of a combination lens.

A focusing optical system 5 is disposed on the optical path of the laser light LB downstream of the collimating optical system 3. The collimating optical system 3 and the focusing optical system 5 are spaced apart from each other, and a reduction optical system 4 is disposed between the collimating optical system 3 and the focusing optical system 5. An optical fiber 6 is disposed on the optical path of the laser light LB downstream of the focusing optical system 5.

The focusing optical system 5 is a lens that focuses each laser light LB toward the optical fiber 6. The focusing optical system 5 has an entrance surface 51 on which the laser light LB is incident and an exit surface 52 from which the laser light LB exits. The entrance surface 51 is configured as a curved convex surface. The exit surface 52 is configured as a flat surface.

The optical fiber 6 is long and has an upstream end face that serves as an incident surface 61, and a downstream end face that serves as an exit surface 62. A plurality of laser beams LB focused by the focusing optical system 5 are incident on the incident surface 61 at once. The laser beams LB pass through the optical fiber 6 and are guided to the exit surface 62, from which they are emitted. There are no particular limitations on the optical fiber 6, and an optical waveguide or the like can be used, for example. The reduction optical system 4 will be described later.

Figure 4 is a diagram showing an example of the configuration of one light source 2. The light source 2 is a direct diode laser, which is a so-called edge-emitting type. The light source 2 has a laser diode element 22, a photodiode 23, and a package 24.

The laser diode element 22 is a light-emitting element that emits laser light (semiconductor laser) LB. The laser diode element 22 is composed of, for example, a laminate having an active layer (light-emitting layer) and an n-type cladding layer and a p-type cladding layer arranged via the active layer. Both end faces of the active layer are reflective surfaces. When a voltage is applied to the laser diode element 22 in the forward direction, electrons flow from the n-type cladding layer into the active layer, and holes flow from the p-type cladding layer into the active layer, recombining in the active layer to emit light. Since the refractive index of each cladding layer is lower than that of the active layer, the light travels back and forth between the both end faces in the active layer while being amplified. Then, stimulated emission occurs, and the light is irradiated as laser light LB.

The laser light LB emitted by the laser diode element 22 (active layer) is not a completely straight light, but spreads as it travels due to diffraction. In addition, the laser diode element 22, which is a laminate, is formed so that the width direction is larger than the thickness direction. This causes the laser light LB to spread in an elliptical shape, and the intensity distribution (far-field pattern) of the laser light LB is such that the beam diameter (beam width) in the fast axis direction of the laser light LB is larger than the beam diameter in the slow axis direction. In this way, the light source 2 is a direct diode laser, and is a so-called end-emitting type, so it outputs laser light whose beam diameter in the fast axis direction is larger than the beam diameter in the slow axis direction.

The package 24 houses the laser diode element 22 and the photodiode 23 together. The package 24 is a so-called CAN-type package, and has a base 241, a cap 242, and a cover glass 243.

The base 241 is disk-shaped and has a disk-shaped portion 244 on which the photodiode 23 is supported, and a support portion 245 formed to protrude from the disk-shaped portion 244 and on which the laser diode element 22 is supported. The disk-shaped portion 244 forms a flange portion of the package 24 with the largest outer diameter. When the light source 2 is fixed to a predetermined position in the light source device 100, the light source 2 can be stably fixed by the disk-shaped portion 244.

A cap 242 is fixed to the base 241. The cap 242 is a member that covers the laser diode element 22 and the photodiode 23 supported by the base 241. The cap 242 also has a through hole 246 formed therein through which the laser light LB passes.

The constituent materials of the base 241 and the cap 242 are not particularly limited, and may be, for example, a metal material such as aluminum. The cover glass 243 is a glass plate that covers the through hole 246 from the inside of the cap 242. The laser light LB can pass through the cover glass 243. The cover glass 243 may be omitted from the package 24. The photodiode 23 detects the power of the laser light emitted from the light source 2. The control device (not shown) can detect a failure of the light source 2 by detecting the presence or absence of laser light from the photodiode 23.

Next, the reduction optical system 4 will be described with reference to Figures 2 and 3. As described above, the intensity distribution of the laser light LB is larger in the fast axis direction than in the slow axis direction. In other words, the beam diameter of the laser light LB is larger in the fast axis direction than in the slow axis direction. Therefore, the beam output from the light source 2 is an elliptical beam with an elliptical cross section. The reduction optical system 4 shapes the elliptical beam by reducing the beam diameter in the larger direction, i.e., the fast axis direction.

Before and after the reduction optical system 4, the beam diameter of the laser light LB that has passed through the collimating optical system 3 is reduced in the fast axis direction, but is maintained constant in the slow axis direction. In other words, in the fast axis direction, the beam diameter of the laser light LB after passing through the reduction optical system 4 is smaller than the beam diameter of the laser light LB before passing through the reduction optical system 4. On the other hand, in the slow axis direction, there is no change in the beam diameter due to passing through the reduction optical system 4.

The reduction optical system 4 has a first cylindrical lens 41 having power in the fast axis direction, and a second cylindrical lens 42. The first cylindrical lens 41 and the second cylindrical lens 42 are arranged in order from the upstream side to the downstream side.

The first cylindrical lens 41 has an incident surface 411 on which the laser light LB is incident, and an exit surface 412 from which the laser light LB is emitted. The incident surface 411 has a convex surface formed so that the protruding height changes continuously along the fast axis direction. On the other hand, the exit surface 412 is configured as a flat surface. Due to such incident surface 411 and exit surface 412, the first cylindrical lens 41 becomes a cylindrical lens having power in the fast axis direction.

The second cylindrical lens 42 has an incident surface 421 on which the laser light LB is incident, and an exit surface 422 from which the laser light LB is emitted. The incident surface 421 has a concave surface 423 formed so that the depth changes continuously along the fast axis direction. On the other hand, the exit surface 422 is configured as a flat surface. With such incident surface 421 and exit surface 422, the second cylindrical lens 42 becomes a cylindrical lens having power in the fast axis direction. With such a reduction optical system 4, the beam diameter in the fast axis direction is reduced as the laser light LB advances.

A power meter 150 (also called a "sensor") may be attached to the light source device 100 by an inspector or the like. The power meter 150 is disposed, for example, on the side of the emission surface 62 of the optical fiber 6. The power meter 150 can display an output physical quantity (described later) related to the output from the optical fiber. Note that the power meter 150 may be attached to another location as long as it can display the output physical quantity.

Next, the holding portion 81 and the wedge plate 82 will be described. The holding portion 81 and the wedge plate 82 are arranged in order from the upstream side to the downstream side in the optical axis direction. The wedge plate 82 is a prism used to correct the output physical quantity, as described later. The holding portion 81 and the wedge plate 82 are arranged, for example, in the abnormal optical path described later. In the example of FIG. 2 and FIG. 3, a case is shown in which the abnormal optical path is the second optical path LD from the top. In addition, the holding portion 81 holds the wedge plate 82. In the example of FIG. 2, an example is shown in which the holding portion 81 is arranged in the central optical path LD, but it may be provided in another optical path LD. The holding portion 81 and the wedge plate 82 may be arranged before the shipment of the light source device 100. In addition, the holding portion 81 and the wedge plate 82 may be arranged later after the shipment of the light source device 100.

Figure 5 is a plan view of the holding portion 81 and the wedge plate 82 from the upstream side in the Z-axis direction. In Figure 5, the wedge plate 82 is indicated by a dashed line. As shown in Figure 5, the holding portion 81 is formed with a through hole 81A. The through hole 81A is a hole through which the laser light LB collimated by the collimating optical system 3 passes. In the example of Figure 5, the through hole 81A is hatched. As described above, the beam diameter of the laser light LB in the fast axis direction is larger than the beam diameter in the slow axis direction, so that the cross section of the laser light LB has an elliptical shape. Therefore, the shape of the through hole 81A is also elliptical. Note that the through hole 81A may have any shape as long as it is a shape through which the laser light from the collimating optical system 3 passes.

6 is a plan view of the wedge plate 82 from the slow axis direction. In the example of FIG. 6, the holding portion 81 is omitted. The wedge plate 82 has an incident surface 82A and an exit surface 82B. The laser light incident on the incident surface 82A of the wedge plate 82 is emitted from the exit surface 82B. The incident surface 82A is perpendicular to the Z axis direction. The exit surface 82B forms a first angle θ1 with the Z axis direction (in FIG. 6, this is indicated as axis ZL). The first angle θ1 is, for example, equal to or greater than 89.5 degrees and less than 90 degrees. The first angle θ1 corresponds to the "non-perpendicular angle" of the present disclosure. Also, FIG. 6 shows a second angle θ2. The second angle θ2 is calculated by subtracting the first angle θ1 from 90 degrees. The second angle θ2 is also referred to as the "wedge angle".

The parallel light incident on the wedge plate 82 is refracted and emitted from the emission surface 82B in a direction different from the direction of incidence. Also, in FIG. 6, a virtual plane Y (for example, a plane) perpendicular to the Z-axis direction (the optical axis direction of the laser light passing through the collimating optical system 3) is shown. The wedge plate 82 is arranged in a manner that allows it to rotate within the virtual plane Y. In other words, the wedge plate 82 is held by the holding unit 81 so that it can rotate around the Z-axis direction. In other words, the wedge plate 82 can rotate on the plane formed by the fast axis and the slow axis. The wedge plate 82 is rotated by the inspector's hand, a jig, an actuator, or the like. Even if the wedge plate 82 is rotated, the holding unit 81 is fixed. The reason why the wedge plate 82 is rotatable will be described later.

As a modified example, the incident surface 82A may form a non-perpendicular angle with the Z-axis direction, and the exit surface 82B may form a non-perpendicular angle with the Z-axis direction. The incident surface 82A may form a non-perpendicular angle with the Z-axis direction, and the exit surface 82B may form a non-perpendicular angle with the Z-axis direction. In other words, the wedge plate 82 has an incident surface 82A and/or an exit surface 82B that form a non-perpendicular angle with respect to the Z-axis direction (optical axis direction).

[Regarding position misalignment]
In the manufacturing process of the light source device 100, target components of the light source device 100 (for example, the N light sources 2 or the N collimating optical systems 3) are fixed by welding, adhesive, or the like. In the following, an example will be described in which the target components are the collimating optical systems 3. In the manufacturing process of the light source device 100, the collimating optical systems 3 may be fixed slightly deviated from the originally planned design position.

In addition, in the manufacture of the light source device 100, all of the target parts of the light source device 100 are fixed in their designed positions before being shipped, but due to deterioration of the light source device 100 over time at the shipping destination, the target parts may shift from their designed positions. For example, the welded parts of the target parts or the parts fixed with adhesive may deteriorate. This deterioration may cause the target parts to shift from their designed positions.

For example, as shown in the upper diagram of FIG. 3, when the collimating optical system 3, which is an example of a target part, shifts by Δx in the fast direction, the focusing position on the incident surface 61 of the optical fiber 6 shifts by Δxf in the fast direction. The focusing position is the position where the N laser beams that have passed through the focusing optical system 5 are focused on the incident surface 61. The focusing position is, for example, a point.

In addition, Δxf is a value proportional to the reduction ratio in the Fast axis direction by the reduction optical system 4. For example, Δxf when the reduction ratio by the reduction optical system 4 is 1/2 is twice as much as Δxf when the reduction optical system 4 is not arranged (i.e., the reduction ratio is 1).

Note that there may be cases where the target component (for example, a collimating optical system) is shifted by Δy on the slow axis. In this case, in this embodiment, the slow axis of the laser light is not reduced. Therefore, even if Δx and Δy are the same value, Δxf is greater than Δyf.

In this way, since the light source device 100 of this embodiment has the reduction optical system 4, the beam diameter in the fast axis direction is reduced, so that it may be possible that the laser light is easily coupled to the core end face of the optical fiber. However, if the target part is displaced from the ideal position, the focusing position on the incident surface 61 of the optical fiber 6 will be significantly displaced in the fast axis direction. As a result, the laser light may not be properly coupled. Therefore, the output from the optical fiber 6 is large relative to the displacement in the fast direction, so the output physical amount decreases. Here, the output physical amount may be the output power of the laser light from the optical fiber 6. The output physical amount may also be the rate of change of the output value (for example, output power) from the optical fiber 6 based on the case where the focusing position on the incident surface 61 is the ideal position. The ideal position is the ideal position of the focusing position, for example, the center or center of gravity of the incident surface 61. The output physical amount may also be the coupling rate of N laser lights. As described above, the target part is a part whose focusing position on the incident surface 61 will be displaced from the ideal position when it is fixed in a displaced manner.

Figure 7 is a diagram showing the relationship between the amount of deviation of the focusing position on the incident surface 61 in the fast axis direction from the design position and the above-mentioned output change rate (corresponding to the above-mentioned output physical quantity). The horizontal axis of Figure 7 shows the amount of deviation of the collimating lens constituting the collimating optical system 3 in the fast axis direction. The unit of the amount of deviation is μm. The vertical axis of Figure 7 shows the output change rate. In the example of Figure 7, for example, when the amount of deviation is 1 μm, the fiber output decreases by 12%. In addition, in order to output appropriate laser light from the optical fiber 6 of the light source device, it is preferable that the output physical quantity from the optical fiber 6 is equal to or greater than the threshold value. In the example of Figure 7, 90% is shown as an example of the threshold value Th of the output change. In addition, the output physical quantity can be displayed by the power meter 150 (see Figure 2) as described above. Note that, as described above, even if Δx and Δy are the same value, Δxf is larger than Δyf. Therefore, even if Δx and Δy are the same value, the rate of decrease in the output physical quantity when the target part (collimating optical system 3) is shifted by Δx is greater than the rate of decrease in the output physical quantity when the target part is shifted by Δy. Therefore, in this embodiment, there is no particular problem even if the target part is shifted by Δy on the slow axis.

Conventionally, after the target part is fixed, the output physical quantity may become less than the threshold value due to misalignment of the target part. In such a case, the inspector adjusts the position of the target part so that the physical quantity becomes equal to or greater than the threshold value.

However, it is difficult to adjust the position of a fixed target part. In addition, the diameter of the N parallel light beams in the fast axis direction is significantly reduced by the reduction optical system 4. Therefore, even if the position of the target part can be adjusted, it will be significantly displaced in the fast axis direction at the incident surface 61 of the optical fiber 6. Therefore, high adjustment accuracy is required for the position of the target part in the fast axis direction.

As described above, in conventional light source devices, a problem can arise in that it is difficult to correct the physical quantity of output from the optical fiber 6. Therefore, the inspector can rotate the wedge plate 82 to change the direction of the parallel light and correct the focusing position in the optical fiber 6.

Figure 8 is a diagram showing the movement of the focusing position by rotating the wedge plate 82. Figure 8(a) is a diagram showing the rotation of the wedge plate 82. Figure 8(b) is a diagram showing the trajectory of the focusing position when the reduction optical system 4 is not arranged. Figure 8(c) is a diagram showing the trajectory of the focusing position when the reduction optical system 4 is arranged. In Figures 8(b) and 8(c), the trajectory of the focusing position is indicated by a dashed line.

The wedge plate 82 can rotate around the Z-axis direction in both the clockwise and counterclockwise directions. In the example of FIG. 8(a), an example is shown in which the wedge plate 82 is rotated by the inspector in the counterclockwise direction. As described above, the parallel light incident on the wedge plate 82 is refracted and emitted from the exit surface 82B in a direction different from the direction of incidence. Therefore, the focusing position on the entrance surface 61 is displaced in response to the rotation of the wedge plate 82.

Figure 8 (b) shows the displacement of the focusing position when the reduction optical system 4 is not arranged. When the reduction optical system 4 is not arranged, as shown in Figure 8 (b), the displacement of the focusing position is the same in the fast axis direction and the slow axis direction.

Figure 8 (c) shows the displacement of the focusing position when the reduction optical system 4 is arranged (i.e., in this embodiment). When the reduction optical system 4 is arranged, as shown in Figure 8 (c), the displacement of the focusing position in the fast axis direction is greater than the displacement of the focusing position in the slow axis direction. This is because the beam diameter of the parallel light in the fast axis direction is reduced by the reduction optical system 4.

Figure 9 shows the relationship between the wedge angle (second angle θ2 in Figure 6) and the maximum change in the focusing position on the incident surface 61 when the wedge plate 82 is rotated. The vertical axis of Figure 9 (A) shows the maximum change in the beam center of gravity in the fast axis direction on the incident surface 61. The vertical axis of Figure 9 (B) shows the maximum change in the beam center of gravity in the slow axis direction on the incident surface 61. The units of the vertical axis of Figure 9 (A) and the vertical axis of Figure 9 (B) are "mm". The horizontal axis of Figures 9 (A) and 9 (B) shows the wedge angle (second angle θ2 in Figure 6).

In the example of FIG. 9(A), the larger the wedge angle, the larger the maximum change in the fast axis direction. For example, when the wedge angle is 0.1 degrees, the maximum change in the fast axis direction is 336 μm. In the example of FIG. 9(B), the larger the wedge angle, the larger the maximum change in the slow axis direction. For example, when the wedge angle is 0.1 degrees, the maximum change in the slow axis direction is 21 μm. The focusing core diameter of the optical fiber 6 is typically 50 μm to 600 μm. In this case, if the wedge angle is within the range of 0.01 degrees to 0.2 degrees, the focusing position in the fast axis direction can be appropriately corrected.

As shown in Figures 9(A) and 9(B), the maximum displacement of the focusing position in the fast axis direction is greater than the maximum displacement of the focusing position in the slow axis direction. The displacement of the focusing position in the fast axis direction is S times (S is a positive real number) the displacement of the focusing position in the slow axis direction. This value of S is based on the reduction ratio of the reduction optical system 4. For example, if the beam diameter of the parallel light in the fast axis direction is reduced to 1/16 by the reduction optical system 4, S becomes "16". The larger the wedge angle, the greater the maximum displacement of the focusing position in the fast axis direction and the slow axis direction.

As described above, the light source 2 in this embodiment is a direct diode laser, which is a so-called edge-emitting type. Therefore, the light source 2 outputs a laser light (elliptical beam) whose beam diameter in the fast axis direction is larger than the beam diameter in the slow axis direction. The reduction optical system 4 reduces the beam diameter in the fast axis direction to shape the elliptical beam. In addition, the target component (for example, the collimating optical system 3 in FIG. 2) may shift by Δx in the fast axis direction. In this case, the focusing position on the incident surface 61 shifts significantly in the fast axis direction (Δxf shift), and the output physical quantity is significantly reduced (see FIG. 7). In conventional light source devices, it was difficult to correct this output physical quantity.

Therefore, the light source device 100 of this embodiment includes a wedge plate 82 having the above-mentioned exit surface 82B. As shown in Figures 9(A) and 9(B), when an inspector rotates the wedge plate 82 around the Z axis, the light focusing position in the fast axis direction can be greatly displaced. Note that the amount of displacement of the light focusing position in the slow axis direction is small. Therefore, the light focusing position can be greatly displaced in the fast axis direction on the incident surface 61 of the optical fiber 6. Therefore, in the light source device 100, the light focusing position can be set to the above-mentioned ideal position or can be brought close to the ideal position, and the output physical quantity can be made equal to or greater than the threshold. As a result, in the light source device 100 of this embodiment, the output physical quantity from the optical fiber can be easily corrected.

[Testing method procedure]
10 is a diagram showing an example of the procedure of the inspection method. The inspection method is performed by an inspector or the like after the light source device 100 is completed in the manufacture of the light source device 100 and before the light source device 100 is shipped. In addition, the inspection method is performed by an inspector (for example, a serviceman) or the like after the light source device 100 is shipped and, for example, when the light source device 100 deteriorates over time due to use by a user at the shipping destination and the user finds an abnormality in the output physical quantity of the light source device 100.

First, in step S2, the inspector attaches the power meter 150 (see FIG. 2) to the light source device 100 and has the power meter display the output physical quantity.

Next, in step S4, the inspector identifies an abnormal optical path from the N optical paths LD (see FIG. 2) in which the output physical quantity is equal to or less than a threshold value. For example, the inspector causes the N light sources to output laser light one by one and visually checks the output physical quantity. For example, the optical path LD corresponding to the light source in which the output physical quantity has decreased is the abnormal optical path. Note that other methods may be used to identify the abnormal optical path.

Next, in step S6, the inspector positions the holder 81 and the wedge plate 82. As described in FIG. 6 and other figures, the wedge plate 82 is positioned so that it can rotate around the Z-axis direction. In the example of FIG. 2 and FIG. 3, the abnormal optical path is the second optical path LD from the top, and the holder 81 and the wedge plate 82 are positioned in the abnormal optical path.

Next, in step S8, the inspector rotates the wedge plate 82 while visually checking the output physical quantity displayed on the power meter 150 until the output physical quantity displayed on the power meter 150 becomes equal to or greater than the threshold value. Then, when the output physical quantity becomes equal to or greater than the threshold value, the inspector stops rotating the wedge plate 82. In this way, step S8 is a step in which the inspector rotates the wedge plate 82 to make the output physical quantity of the optical fiber 6 equal to or greater than the threshold value.

At least one process of the inspection method of FIG. 10 may be performed by a control device (not shown) of the light source device 100.

The light source device 100 may be configured not to have the wedge plate 82. In this case, when an abnormal optical path is identified by an inspector in the inspection method, a wedge plate is subsequently placed in the abnormal optical path.

The light source device 100 may also have a wedge plate 82 in at least one of the N optical paths LD. In such a configuration, if the optical path in which the wedge plate 82 is arranged is an abnormal optical path, the inspector corrects the output physical quantity by rotating the wedge plate. On the other hand, if the optical path in which the wedge plate 82 is not arranged is an abnormal optical path, the inspector subsequently places a new wedge plate 82 in the abnormal optical path. Then, the inspector corrects the output physical quantity by rotating the new wedge plate.

As described above, the light source device 100 can easily correct the output physical quantity from the optical fiber 6 by adjusting the wedge plate 82.

For example, a configuration (hereinafter also referred to as a "comparative configuration") in which the wedge plate 82 is disposed in the optical path LD1 between the first cylindrical lens 41 and the second cylindrical lens 42, or in the optical path LD2 between the second cylindrical lens 42 and the focusing optical system 5 can be considered. Here, the diameter of the optical path LD1 or the diameter of the optical path LD2 is smaller than the diameter of the optical path LD. The wedge plate 82 needs to be disposed in the abnormal optical path, but must not extend into the normal optical path that is different from the abnormal optical path. If the wedge plate 82 extends into the normal optical path, the output direction of the normal laser light passing through the normal optical path will change.

Therefore, in the case of a configuration in which the wedge plate 82 is arranged on the optical path LD1 or the optical path LD2, a small wedge plate 82 is required and the positioning accuracy of the wedge plate 82 needs to be increased. Therefore, it is difficult to arrange the wedge plate 82 on the optical path LD1 or the optical path LD2. In contrast, in this embodiment, the wedge plate 82 is arranged on the optical path LD between a specific collimating optical system among the N collimating optical systems 3 and the reduction optical system 4. Therefore, compared to the comparative configuration, a larger wedge plate 82 can be used and there is no need to increase the positioning accuracy of the wedge plate 82. Therefore, the inspector can easily arrange the wedge plate 82.

The specific collimating optical system 3 is a lens through which laser light passes, the output physical quantity of which is less than the threshold value, assuming that the wedge plate 82 does not exist. In other words, the specific collimating optical system 3 is the collimating optical system corresponding to the abnormal optical path (the second collimating optical system 3 from the top in the examples of Figures 2 and 3). Therefore, the inspector can adjust the wedge plate 82 to make the output physical quantity equal to or greater than the threshold value.

In addition, the beam diameter in the fast axis direction of the laser light output from the N light sources 2 is larger than the beam diameter in the slow axis direction. In other words, existing light sources 2 (for example, edge-emitting light sources or direct diode lasers) can be used. In this way, even if existing light sources 2 are used, the inspector can correct the output physical quantity by rotating the new wedge plate.

The first angle θ1 of the wedge plate 82 is an angle in the range of 89.5 degrees or more and less than 90 degrees. The inventors discovered that by having the first angle θ1 within this range, it is possible to increase the amount of displacement of the focusing position on the incident surface 61 in the fast axis direction and reduce the aberration of the laser light that has passed through the wedge plate 82. Therefore, by having the first angle θ1 within this range, it is possible to reduce the aberration of the laser light.

Second Embodiment
In the first embodiment, a configuration has been described in which the beam diameter in the fast axis direction of the laser light output from the N light sources 2 is larger than the beam diameter in the slow axis direction. In the first embodiment, a configuration has been described in which the reduction optical system 4 reduces the beam diameter in the fast axis direction of the laser light, thereby shaping the elliptical beam only in the fast axis direction. In the second embodiment, a configuration has been described in which the beam diameter in the slow axis direction of the laser light is expanded by the expansion optical system, thereby shaping the elliptical beam only in the slow axis direction. The "expansion optical system" corresponds to the "beam diameter adjustment optical system" in this disclosure.

Figure 11 is a diagram showing an example of the configuration of the light source device 100A of the second embodiment. The upper diagram of Figure 11 shows the light source device 100A when viewed in a plan view from the fast axis direction of the laser light, and the lower diagram of Figure 3 shows the light source device 100A when viewed in a plan view from the slow axis direction of the laser light.

Comparing Figures 3 and 11, in Figure 11, the reduction optical system 4 in Figure 3 has been replaced with a magnification optical system 160.

The magnifying optical system 160 has a third cylindrical lens 43 having power in the fast axis direction, and a fourth cylindrical lens 44. The third cylindrical lens 43 and the fourth cylindrical lens 44 are arranged in order from the upstream side to the downstream side.

The third cylindrical lens 43 has an incident surface 431 on which the laser light LB is incident, and an exit surface 432 from which the laser light LB is emitted. The incident surface 431 is configured as a flat surface. On the other hand, the exit surface 432 has a convex surface formed so that the protruding height changes continuously along the fast axis direction. Due to such incident surface 431 and exit surface 432, the third cylindrical lens 43 becomes a cylindrical lens having power in the fast axis direction.

The fourth cylindrical lens 44 has an incident surface 441 on which the laser light LB is incident and an exit surface 442 from which the laser light LB is emitted. The incident surface 441 is configured as a flat surface. On the other hand, the exit surface 442 is configured as a concave surface 443 formed so that the depth changes continuously along the fast axis direction. With such incident surface 441 and exit surface 442, the fourth cylindrical lens 44 becomes a cylindrical lens having power in the fast axis direction. With such an expansion optical system 160, the beam diameter in the slow axis direction is expanded as the laser light LB advances. In addition, the wedge plate 82 is disposed, for example, in the optical path between the specific collimating optical system described above and the expansion optical system 160.

The light source device 100A of the second embodiment has the same effects as the light source device 100 of the first embodiment. In addition, the inspection method described in FIG. 10 can be performed on the light source device 100A of the second embodiment.

Third Embodiment
In the first embodiment, the light source device 100 is applied to the processing device 10. In the third embodiment, the light source device 100 is applied to the projector 15. Fig. 12 is a functional block diagram of the projector 15 to which the light source device of this embodiment is applied. The projector 15 displays a predetermined screen (moving image or still image) by irradiating the screen S with laser light.

The projector 15 includes M (M is an integer of 1 or more) light source devices and a projection head 132. Laser light of a different wavelength is output from the light source 2 of each of the M light source devices. M is, for example, 3. For example, the M light source devices include a light source device 100R that outputs red laser light, a light source device 100G that outputs green laser light, and a light source device 100B that outputs blue laser light. The projection head 132 emits the laser light output from the M light source devices toward the screen S. The projection head 132 has, for example, a focusing optical system that focuses the laser light output from the M light source devices. The laser light output from the projection head 132 is irradiated onto the screen S.

In this way, the light source device of the present disclosure can also be applied to a projector. However, the light source device may also be applied to other devices.

[Aspects]
It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

(1) A light source device according to one embodiment includes a plurality of light sources that output laser light, a plurality of collimating optical systems that collimate the laser light output from the plurality of light sources, a beam diameter adjustment optical system that reduces the beam diameter in the fast axis direction of each of the laser light that has passed through the plurality of collimating optical systems, or expands the beam diameter in the slow axis direction of each of the laser light, a focusing optical system that focuses the laser light that has passed through the beam diameter adjustment optical system, an optical fiber into which the laser light focused by the focusing optical system is input, and a wedge plate that is arranged in a rotatable manner within a plane perpendicular to the optical axis direction of the laser light that has passed through the plurality of collimating optical systems, and the wedge plate has an entrance surface and/or an exit surface that are non-perpendicular to the optical axis direction.

With this configuration, the wedge plate can be rotated by an inspector or the like to displace the focusing position on the incident surface of the optical fiber in the fast axis direction. As a result, the light source device can easily correct the physical quantity related to the output from the optical fiber.

(2) In the light source device described in 1, the collimating optical system is disposed between a specific collimating optical system among the multiple collimating optical systems and the beam diameter adjustment optical system.

With this configuration, the optical path diameter between a specific collimating optical system and the optical system is large, so the examiner can easily position the wedge plate.

(Clause 3) In the light source device described in paragraphs 1 and 2, each of the multiple light sources outputs laser light whose beam diameter in the fast axis direction is larger than the beam diameter in the slow axis direction.

With this configuration, the laser light can be shaped into a circular laser light in the optical system, and the fast axis direction can be displaced more than the slow axis direction on the incident surface of the optical fiber.

(4) In the light source device described in any one of paragraphs 1 to 3, the non-right angle is 89.5 degrees or more and less than 90 degrees.

With this configuration, the aberration of the laser light can be reduced.
(5) A processing device according to one aspect includes the light source device according to any one of the first to fourth aspects, and a processing head that emits laser light output from the light source device toward a workpiece.

With this configuration, in a processing device capable of processing an object to be processed, the physical quantities related to the output from the light source device can be easily corrected.

(6) An inspection method according to one embodiment is a method for inspecting a light source device, the light source device comprising: a plurality of light sources that output laser light; a plurality of collimating optical systems that collimate the laser light output from the plurality of light sources; a beam diameter adjustment optical system that reduces the beam diameter in the fast axis direction of each of the laser lights that have passed through the plurality of collimating optical systems, or expands the beam diameter in the slow axis direction of each of the laser lights; a focusing optical system that focuses the laser light that has passed through the beam diameter adjustment optical system; and an optical fiber into which the laser light focused by the focusing optical system is input; the inspection method comprises disposing a wedge plate in a rotatable manner within a plane perpendicular to the optical axis direction of the laser light that has passed through the plurality of collimating optical systems, the wedge plate having an entrance surface and/or an exit surface that have a non-perpendicular angle with respect to the optical axis direction; and the inspection method further comprises rotating the wedge plate to set a physical quantity related to the output of the optical fiber to a threshold value or more.

With this configuration, the wedge plate can be rotated by an inspector or the like to displace the focusing position on the incident surface of the optical fiber in the fast axis direction. As a result, the light source device can easily correct the physical quantity related to the output from the optical fiber.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present disclosure is indicated by the claims rather than the description of the embodiments above, and is intended to include all modifications within the meaning and scope of the claims.

2 light source, 3 collimating optical system, 4 reduction optical system, 5 focusing optical system, 6 optical fiber, 10 processing device, 15 projector, 22 laser diode element, 23 photodiode, 24 package, 41 first cylindrical lens, 42 second cylindrical lens, 43 third cylindrical lens, 44 fourth cylindrical lens, 82A incident surface, 82B exit surface, 81 holding portion, 81A through hole, 82 wedge plate, 100 light source device, 130 processing head, 132 projection head, 150 power meter, 160 magnifying optical system, 241 base, 242 cap, 243 cover glass, 244 disk-shaped portion, 245 support portion, 246 through hole.

Claims (6)

A plurality of light sources that output laser light;
a plurality of collimating optical systems each collimating the laser light output from the plurality of light sources;
a beam diameter adjusting optical system that reduces a beam diameter in a fast axis direction of each of the laser beams that have passed through the plurality of collimating optical systems, or expands a beam diameter in a slow axis direction of each of the laser beams;
a focusing optical system that focuses the laser light that has passed through the beam diameter adjusting optical system;
an optical fiber into which the laser light focused by the focusing optical system is input;
a wedge plate arranged in a rotatable manner within a plane perpendicular to the optical axis direction of the laser light having passed through the plurality of collimating optical systems;
The wedge plate is
a specific collimating optical system among the plurality of collimating optical systems and the beam diameter adjusting optical system,
A light source device having an entrance surface and/or an exit surface that are non-perpendicular to the optical axis direction. 2. The light source device according to claim 1, wherein the specific collimating optical system is a collimating optical system corresponding to a light source among the plurality of light sources for which a physical quantity relating to an output from the optical fiber is less than a threshold value when the wedge plate is not disposed. The light source device according to claim 1 or 2, wherein each of the plurality of light sources outputs laser light whose beam diameter in the fast axis direction is larger than the beam diameter in the slow axis direction. The light source device according to any one of claims 1 to 3, wherein the non-perpendicular angle is equal to or greater than 89.5 degrees and less than 90 degrees. A light source device according to any one of claims 1 to 4,
and a processing head that emits the laser light output from the light source device toward a workpiece. A method for inspecting a light source device, comprising:
The light source device is
A plurality of light sources that output laser light;
a plurality of collimating optical systems each collimating the laser light output from the plurality of light sources;
a beam diameter adjusting optical system that reduces a beam diameter in a fast axis direction of each of the laser beams that have passed through the plurality of collimating optical systems, or expands a beam diameter in a slow axis direction of each of the laser beams;
a focusing optical system that focuses the laser light that has passed through the beam diameter adjusting optical system;
an optical fiber into which the laser light focused by the focusing optical system is input,
The inspection method includes disposing a wedge plate between a specific collimating optical system among the plurality of collimating optical systems and the beam diameter adjusting optical system in a manner that the wedge plate can rotate within a plane perpendicular to an optical axis direction of the laser light that has passed through the plurality of collimating optical systems ;
the wedge plate has an entrance surface and/or an exit surface that is non-perpendicular to the optical axis direction;
The inspection method further comprises:
The inspection method includes rotating the wedge plate to make a physical quantity related to the output of the optical fiber equal to or greater than a threshold value.

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