JP7565582B2 - Laser soldering apparatus and method - Google Patents

Description

The present invention relates to a laser soldering device and method that uses laser light to perform soldering, and in particular to a soldering device and method that are suitable for point soldering, in which multiple soldering points are soldered one by one in sequence.

Technology for soldering electronic components to printed circuit boards using laser light is well known, as disclosed in, for example, Patent Document 1. As an example, Figures 7 to 11 show a schematic diagram of a method for soldering a soldering point P consisting of an annular land 61 formed on a printed circuit board 60 and a rod-shaped lead 62 extending from an electronic component 63, using laser light B and linear solder 64. The part marked with the reference symbol 65 in Figure 7 is an irradiation head for irradiating the laser light B.

In the method, first, as shown in FIG. 7 and FIG. 8, the laser light B from the irradiation head 65 is irradiated onto the land 61 and the lead 62 to preheat the land 61 and the lead 62 to a set temperature (first step), then, as shown in FIG. 9(a) and (b), linear solder 64 is supplied from the solder supply nozzle 66 and melted, and the molten solder (molten solder) 64a is diffused over the entire soldering point P (second step), and then, as shown in FIG. 10, the diffused molten solder 64a is post-heated with the laser light B (third step), thereby completing the soldering of the land 61 and the lead 62 as shown in FIG. 11.

By the way, various kinds of metals are used to form the land 61 and the lead 62. For example, the land 61 is made of copper or tin-plated copper, and the lead 62 is made of copper or gold-plated copper. The metal that constitutes the linear solder 64 is mainly tin.

It is generally known that when the metal materials constituting the soldering point are different in this way, the spectral characteristics (absorption characteristics) of the laser light B are different. For example, when using a laser light with a wavelength of 700-1100 nm, tin has the highest absorption rate of the laser light, followed by copper, and then gold. This makes it easy for a difference to occur in the heating time between the land 61 and the lead 62. For example, if the land 61 is made of copper plated with tin and the lead 62 is made of copper plated with gold, in the first step of preheating the land 61 and the lead 62, the land 61 reaches the set temperature quickly, but the lead 62 reaches the set temperature slower. This means that it takes a long time to heat the entire soldering point to the required temperature, which causes problems with heating efficiency.

In order to solve these problems, the applicant has proposed a soldering device as disclosed in Patent Document 2. This soldering device takes advantage of the fact that it is known that copper, gold, or tin have a higher absorption rate for short-wavelength laser light than for long-wavelength laser light, and in the first step of preheating the land and lead, a short-wavelength laser light is irradiated onto the soldering point, and in the second step and thereafter, after the solder has been supplied, a long-wavelength laser light is irradiated onto the soldering point.

The soldering device uses a short-wavelength laser light in the preheating process, which allows the leads to be heated to the set temperature in a short time, making it highly efficient at heating. However, because the short-wavelength laser light is irradiated onto the entire soldering point, the temperature of components other than the leads (lands, boards, electronic components, etc.) also rises quickly. For this reason, it is necessary to monitor these temperatures to prevent them from rising too high.

Patent document 3 discloses a laser processing device that has multiple semiconductor lasers, an optical fiber focusing section that focuses multiple optical fibers into which the laser light from each semiconductor laser enters, and a focusing lens that focuses the laser light emitted from the optical fiber focusing section, and irradiates the laser light from the optical fiber focusing section toward the workpiece in a pattern such as a concentric circle, pyramid, rectangle, line, or ring shape.

However, because this laser processing device emits laser light of the same intensity from multiple optical fibers, even if it is directly applied to point soldering, it will have the same problems as the device disclosed in Patent Document 1. The multiple semiconductor lasers can be individually turned on and off or have their output adjusted, but this operation is performed by selectively driving the semiconductor lasers to correspond to individual patterns when the terminal arrangement patterns of the flat package ICs to be soldered are different, or by adjusting the overall intensity of the laser light output from the multiple optical fibers.

JP 2008-173659 A JP 2020-93296 A Japanese Patent Application Publication No. 2-142695

The technical objective of the present invention is to make it possible to heat the entire soldering point to a set temperature evenly and efficiently in a short time, even when the metal materials that make up the soldering point are different.

In order to solve the above problems, according to the present invention, there is provided a laser beam generating apparatus comprising: a plurality of laser oscillators each capable of controlling an output individually; a plurality of optical fibers individually connected to the plurality of laser oscillators and bundled together; a focusing lens for focusing a laser beam bundle which is a bundle of laser light emitted from the light emitting surfaces of the plurality of optical fibers; and a control device for controlling the plurality of laser oscillators, wherein the plurality of optical fibers are bundled in an array pattern in which the light emitting surface of one optical fiber located at the center is surrounded by the light emitting surfaces of the other optical fibers , so that the laser beam bundle emitted from the light emitting surface and focused by the focusing lens is irradiated onto one soldering point consisting of an annular land and a rod-shaped lead inserted into a through hole of the land. and the control device is capable of individually adjusting the intensity of the laser light emitted from each of the optical fibers in accordance with the condition of the portion to be irradiated with each laser light by individually controlling the output of the plurality of laser oscillators , thereby emitting a high-intensity laser light from the light output surface located at the center to irradiate the lead, and emitting a laser light of a lower intensity from the other light output surfaces to irradiate the land, or emitting a high-intensity laser light from the other light output surfaces to irradiate the land, and emitting a laser light of a lower intensity from the light output surface located at the center to irradiate the lead .

In this case, the plurality of laser oscillators may emit infrared laser light having a wavelength selected from the wavelength range of 700-1100 nm.

Furthermore, among the multiple laser oscillators, a laser oscillator to which an optical fiber having a light output surface located at the center of the array pattern is connected may emit visible laser light, and the laser oscillators to which the other optical fibers are connected may emit infrared laser light .

In this case, it is preferable that, among the plurality of laser oscillators, a laser oscillator to which an optical fiber having a light output surface located at the center of the array pattern is connected emits visible laser light having a wavelength selected from the wavelength range of 400-690 nm, and the other laser oscillators emit infrared laser light having a wavelength selected from the wavelength range of 700-1100 nm .

According to the present invention, there is also provided a laser soldering method using a soldering device having a plurality of laser oscillators capable of individually controlling outputs, a plurality of optical fibers individually connected to the plurality of laser oscillators and bundled together, and a condenser lens for condensing a laser beam which is a bundle of laser light emitted from the light output surfaces of the plurality of optical fibers, and irradiating one soldering point with the laser beam condensed by the condenser lens to melt the solder supplied to the soldering point, thereby soldering a plurality of soldering points one by one in order, the soldering point comprising an annular land and a rod-shaped lead inserted into a through hole of the land, and the arrangement pattern of the light output surfaces of the plurality of optical fibers is such that a centrally located a light output surface of the soldering element surrounded by other light output surfaces, and by individually controlling the outputs of the plurality of laser oscillators before or during soldering, the intensities of the laser lights emitted from the plurality of optical fibers are individually adjusted according to the conditions of the portions to be irradiated with the laser lights, thereby emitting a high-intensity laser light from the light output surface located in the center to irradiate the lead, and emitting laser lights of lower intensity from the other light output surfaces to irradiate the land, or emitting a high-intensity laser light from the other light output surfaces to irradiate the land, and emitting a laser light of lower intensity from the light output surface located in the center to irradiate the lead .

In this case, the plurality of laser oscillators may emit infrared laser light having a wavelength selected from the wavelength range of 700-1100 nm.

Furthermore, the laser light emitted from the light output surface located at the center of the array pattern among the light output surfaces of the plurality of optical fibers may be visible laser light, and the laser light emitted from the other light output surfaces may be infrared laser light. In this case, it is preferable that the laser light emitted from the light output surface located at the center of the wiring pattern among the light output surfaces of the plurality of optical fibers is visible laser light having a wavelength selected from the wavelength range of 400-690 nm, and the laser light emitted from the other light output surfaces is infrared laser light having a wavelength selected from the wavelength range of 700-1100 nm.

According to the present invention, even if the soldering point is made up of various metal materials with different laser light absorption rates, the output of multiple laser oscillators can be individually controlled to adjust the intensity of the laser light emitted from multiple optical fibers individually according to the condition of the area to which each laser light is irradiated , thereby making it possible to uniformly heat the entire soldering point to the target temperature in a short period of time, thereby improving heating efficiency and enabling high-precision soldering.

1 is a schematic diagram showing an embodiment of a laser soldering device according to the present invention; 1 is a front view showing the arrangement pattern of the light output surfaces of the tips of optical fibers bundled together as a fiber bundle. FIG. 2 is an enlarged view of a main part of FIG. 1 . FIG. 4 is an enlarged plan view of the soldering point in FIG. 3 . 1A is a cross-sectional view showing a first soldering step, FIG. 1B is a cross-sectional view showing a second soldering step, and FIG. 1C is a cross-sectional view showing a third soldering step. 1A is a schematic diagram showing another example of the intensity distribution of focused laser light, and FIG. 1B is a schematic diagram showing yet another example of the intensity distribution of focused laser light. FIG. 1 is a cross-sectional view of a main part showing a manner in which soldering is performed using a known soldering device. FIG. 1 is a perspective view of a main portion showing a first step of a known soldering process. 13A and 13B are perspective views of a main part showing a second step of a known soldering process. FIG. 13 is a perspective view of a main part showing a third step of the known soldering process. 1 is a perspective view of a soldered portion after a known soldering process is completed; FIG.

The laser soldering device and the laser soldering method according to the present invention will be described in detail below with reference to the drawings.

First, one embodiment of the laser soldering apparatus 1 will be described.
As shown in FIG. 1, the laser soldering apparatus 1 includes a plurality of (seven in the illustrated example) laser oscillators L1, L2, L3, L4, L5, L6, and L7 that emit laser beams B1, B2, B3, B4, B5, B6, and B7, a plurality of (seven in the illustrated example) optical fibers F1, F2, F3, F4, F5, F6, and F7 that are individually connected to the plurality of laser oscillators L1-L7, an irradiation head 2 that irradiates a soldering point P on a printed circuit board 3 with the laser beams B1-B7 emitted from the plurality of optical fibers F1-F7, a soldering nozzle 4 that supplies linear solder 5 to the soldering point P, a radiation thermometer 6 that receives infrared rays radiated from the soldering point P and measures the temperature of the soldering point P in a non-contact manner, and a control device 7 that controls the entire laser soldering apparatus 1. The radiation thermometer 6 is connected to a control device 7, and the solder nozzle 4 is connected to a solder supply device (not shown).

As shown in Figures 3 and 4, the soldering point P is composed of an annular land 10 formed on the printed circuit board 3 and a rod-shaped lead 11 extending from an electronic component 12, and the lead 11 is inserted from below upward into the through hole 10a of the land 10. The land 10 is formed by tin plating copper, and the lead 11 is formed by gold plating copper.

The seven laser oscillators L1-L7 generate the laser beams B1-B7 by pumping laser diodes, and are of the same configuration to generate laser beams of the same wavelength, and the output can be individually controlled by the control device 7. For example, infrared laser beams having a wavelength selected from the wavelength range of 700-1100 nm are used as the laser beams B1-B7.

In FIG. 1, the seven optical fibers F1-F7 are bundled together by connecting the base ends of each of them to the seven laser oscillators L1-L7, respectively, to form a bundle fiber 13. The arrangement of the optical fibers F1-F7 in the bundle fiber 13 is such that one optical fiber F1 (first optical fiber) is arranged at the center, and the remaining six optical fibers F2-F7 (second to seventh optical fibers) are arranged evenly around it along the circumference, as shown in FIG. 2. Therefore, at the tip of the bundle fiber 13, the light exit surfaces Fp1, Fp2, Fp3, Fp4, Fp5, Fp6, and Fp7 at the tips of the seven optical fibers F1-F7 are arranged in the same arrangement pattern as the arrangement of the seven optical fibers F1-F7, and seven laser beams B1-B7 are emitted from these seven light exit surfaces Fp1-Fp7 as a laser beam Bf in a bundle state.

The arrangement pattern of the seven light output surfaces Fp1-Fp7 is adapted to the shape of one of the soldering points P, i.e., the shape and arrangement of the land 10 and lead 11. Therefore, as shown by the dashed line in FIG. 4, the laser light B1 emitted from the first light output surface Fp1 in the center irradiates the lead 11, and the laser light B2-B7 emitted from the second to seventh light output surfaces Fp2-Fp7 around it irradiates the annular land 10.

The member indicated by the reference numeral 14 in FIG. 1 is a connector for connecting the bundle fiber 13 to the irradiation head 2.

The irradiation head 2 has a fiber connection part 16 on the side of the housing 15 for connecting the bundle fiber 13 via the connector 14, and inside the housing 15, there are parallel lenses 17a, 17b that collimate the laser beam Bf emitted from the tip of the bundle fiber 13 along the second optical axis S2, a semi-transparent mirror 18 that reflects the parallel laser beam Bf in a direction along the first optical axis S1 perpendicular to the second optical axis S2, and focusing lenses 19a, 19b that focus the laser beam Bf reflected by the semi-transparent mirror 18. The laser beam Bf focused by the focusing lenses 19a, 19b is irradiated to the soldering point P in the manner shown in FIG. 4.

The parallel lens 17a and the condenser lens 19a are composed of an achromatic lens. This achromatic lens is a compound lens in which a convex lens and a concave lens with different refractive indices are bonded together. However, instead of the achromatic lens, a normal convex lens can be used as the parallel lens 17a and the condenser lens 19a.
The semitransparent mirror 18 reflects the laser light beam Bf emitted from the bundle fiber 13 but transmits other visible light.

A CCD camera 20 for imaging the soldering point P is attached to the side of the housing 15, and inside the housing 15, a reflector 21 is arranged at an angle of 45 degrees to the first optical axis S1 to reflect the visible light VL emitted from the soldering point P and transmitted through the semi-transparent mirror 18 along the first optical axis S1 in the direction of the third optical axis S3 passing through the CCD camera 20. An imaging lens 22 is arranged to image the visible light VL reflected by the reflector 21 on the CCD camera 20. The image of the soldering point P captured by the CCD camera 20 is displayed on a monitor (not shown). The imaging lens 22 is also composed of an achromatic lens, but can also be composed of a normal convex lens.

Next, we will explain how to solder the soldering point P using the laser soldering device 1 having the above configuration.

In FIG. 1-FIG. 5, the land 10 constituting the soldering point P is formed by tin plating copper, and the lead 11 is formed by gold plating copper, so that the absorption rate of the infrared laser light is lower in the lead 11. For this reason, prior to soldering, the control device 7 controls the output of the laser oscillators L1-L7, and the output of the first laser oscillator L1 is made larger than the output of the second to seventh laser oscillators L2-L7, so that the intensity of the laser light B1 emitted from the first optical fiber F1 toward the lead 11 is made larger than the intensity of the laser light B2-B7 emitted from the other second to seventh optical fibers F2-F7 toward the land 10. In other words, the intensity of the laser light B1-B7 emitted from the multiple optical fibers F1-F7 is individually adjusted according to the portion to which each laser light B1-B7 is irradiated, so that the intensity distribution is made to match the state of the soldering point P, i.e., the shape and metal material of the soldering point P.

After the intensity adjustment is completed, the seven laser oscillators L1-L7 are started by the control device 7 while maintaining the adjusted state, and the laser beams B1-B7 emitted from each of the laser oscillators L1-L7 are irradiated to the soldering point P in the manner shown in FIG. 4 as the laser beam Bf consisting of the bundle of the seven laser beams B1-B7 through the bundle fiber 13, which is a bundle of the seven optical fibers F1-F7, the parallel lenses 17a, 17b, the semitransparent mirror 18, and the condenser lenses 19a, 19b, and the first step (see FIG. 5(a)) of preheating the land 10 and the lead 11 is performed. At this time, the intensity of the laser beam B1 that heats the lead 11 is greater than the intensity of the laser beams B2-B7 that heat the land 10, so that even the lead 11, which has a low infrared absorption rate, is heated quickly and rises to the target temperature almost at the same time as the land 10.

The temperature of the soldering point P is measured by a radiation thermometer 6, and when the measured temperature reaches a preset target temperature, the first step ends and the process moves to the second step (see FIG. 5(b)) in which the solder line 5 is supplied. In this second step, the irradiation of the laser beam Bf continues, and the supplied solder line 5 melts as it comes into contact with the heated lands 10 and leads 11, and the molten solder 5a spreads over the entire soldering point P.

When the molten solder 5a has diffused over the entire soldering point P, the second step is completed and the process moves to the third step (see FIG. 5(c)). In this third step, the laser beam Bf is continuously irradiated for a certain period of time, whereby the diffused molten solder 5a is post-heated, during which time a metal compound necessary for soldering is generated.
When the third step is completed, the laser oscillators L1-L7 are stopped to stop the irradiation of the laser beam Bf, and the temperature measurement by the radiation thermometer 6 is also stopped, completing the soldering of the soldering point P.

Then, the irradiation head 2 moves toward the next soldering point P, and the first to third steps are performed sequentially for the next soldering point P, and the above-mentioned operations are then repeated for all soldering points P.

In this way, by performing soldering while individually adjusting the intensity of the laser beams B1-B7 irradiated to the soldering point P according to the condition of the area irradiated by each of the laser beams B1-B7, the entire soldering point P can be heated evenly to the target temperature in a short time, even if the soldering point P is made of various metal materials that have different laser light absorption rates. As a result, heating efficiency is improved and high-precision soldering can be performed.

In the above example, the output of the laser oscillators L1-L7 is adjusted before soldering and soldering is performed while maintaining the adjusted state, but the output of each laser oscillator L1-L7 can also be adjusted during soldering. For example, in the first step, the output of the first laser oscillator L1 is set to high output and the output of the other laser oscillators L2-L7 is set to a slightly lower medium output to preheat the soldering point P, in the first half of the second step, in order to prevent the temperature of the soldering point P from dropping due to the melting of the linear solder 5, the output of the first laser oscillator L1 is set to high output and the output of the other laser oscillators L2-L7 is also set to high output, in the second half of the second step, in order to prevent the soldering point P from being overheated after the temperature of the molten solder 5a has stabilized, the output of the first laser oscillator L1 is set to high output and the output of the other laser oscillators L2-L7 is set to low output lower than medium output, and in the third step, the output of all laser oscillators L1-L7 is set to medium output to perform post-heating.

In the above example, the seven laser oscillators L1-L7 are of the same configuration and generate laser light of the same wavelength, but at least one of the seven laser oscillators L1-L7 may emit laser light of a different wavelength from the laser light emitted by the other laser oscillators. For example, the first laser oscillator L1 connected to the first optical fiber F1 having the first light output surface Fp1 located at the center of the array pattern may emit visible laser light such as blue or green having a wavelength of 400-690 nm, and the second to seventh laser oscillators L2-L7 connected to the other second to seventh optical fibers F2-F7 may emit infrared laser light having a wavelength of 700-1100 nm. This allows the gold-plated lead 11 to be heated more efficiently in a shorter time because the gold-plated lead 11 has a high absorption rate of laser light with a short wavelength.

Furthermore, depending on the shape and condition of the soldering point P, the intensity distribution of the laser light can be made different from the example described above. For example, if the laser light absorptance of the land 10 is lower than that of the lead 11, the output of the second to seventh laser oscillators L2-L7 can be set to high output and the output of the first laser oscillator L1 can be set to low output, so that the laser light B2-B7 emitted from the second to seventh optical fibers F2-F7 can be made high intensity and the laser light B1 emitted from the first optical fiber F1 can be made low intensity, as shown in FIG. 6(a). Also, depending on the shape and arrangement of the land 10 and the lead 11, as shown in an example in FIG. 6(b), the laser beams B1, B2, and B5 emitted from the first, second, and fifth optical fibers F1, F2, and F5 arranged in a row can be made high intensity, while the laser beams B3, B4, B6, and B7 emitted from the third, fourth, sixth, and seventh optical fibers F3, F4, F6, and F7 can be made low intensity or zero intensity, or vice versa.

When soldering soldering points P of different sizes, the spot diameter of each laser beam B1-B7 can be adjusted to match the size of the soldering point P by adjusting the distance from the focusing lenses 19a, 19b to the soldering point P.

Furthermore, in the above embodiment, the spot diameters of the multiple laser beams B1-B7 are the same, but the spot diameters can be different depending on the shape and size of the area to which each laser beam is irradiated. For example, the spot diameter of the laser beam located at the center of the array pattern can be made small and the spot diameters of the laser beams located around it can be made larger, or conversely, the spot diameter of the laser beam located at the center can be made large and the spot diameters of the laser beams located around it can be made smaller. In this case, the thicknesses of the optical fibers will differ depending on the difference in spot diameter. Also, in each embodiment, adjacent laser beams do not necessarily need to be in contact with each other, and it is acceptable for there to be some space between them.

REFERENCE SIGNS LIST 1 laser soldering device 7 control device 10 land 10a through hole 11 lead 19a, 19b condenser lens L1, L2, L3, L4, L5, L6, L7 laser oscillator B1, B2, B3, B4, B5, B6, B7 laser light F1, F2, F3, F4, F5, F6, F7 optical fiber Fp1, Fp2, Fp3, Fp4, Fp5, Fp6, Fp7 light output surface Bf laser light flux P soldering point

Claims (8)

The laser beam source includes a plurality of laser oscillators each capable of controlling an output thereof, a plurality of optical fibers each connected to the plurality of laser oscillators and bundled together, a focusing lens for focusing a laser beam bundle which is a bundle of laser beams emitted from the light exit surfaces of the plurality of optical fibers, and a control device for controlling the plurality of laser oscillators,
the plurality of optical fibers are bundled in an array pattern in which the light output surface of one optical fiber located at the center is surrounded by the light output surfaces of the other optical fibers , so that a laser beam emitted from the light output surface and focused by the focusing lens is irradiated onto one soldering point consisting of an annular land and a rod-shaped lead inserted into a through hole of the land ;
The control device can individually control the outputs of the multiple laser oscillators, thereby individually adjusting the intensity of the laser light emitted from each of the multiple optical fibers in accordance with the condition of the portion to be irradiated with each laser light, and is thus configured to emit a high-intensity laser light from the light output surface located at the center to irradiate the lead, and emit laser light of a lower intensity from the other light output surfaces to irradiate the land, or emit a high-intensity laser light from the other light output surfaces to irradiate the land, and emit a laser light of a lower intensity from the light output surface located at the center to irradiate the lead.
A laser soldering apparatus comprising: 2. The laser soldering apparatus according to claim 1 , wherein said plurality of laser oscillators emit infrared laser light having a wavelength selected from a wavelength range of 700-1100 nm. 2. The laser soldering apparatus according to claim 1, wherein among the plurality of laser oscillators, a laser oscillator connected to an optical fiber having a light output surface located at the center of the array pattern emits visible laser light, and the laser oscillators connected to the other optical fibers emit infrared laser light. 4. The laser soldering apparatus according to claim 3, wherein among the plurality of laser oscillators , a laser oscillator connected to an optical fiber having a light exit surface located at the center of the array pattern emits visible laser light having a wavelength selected from a wavelength range of 400-690 nm, and the other laser oscillators emit infrared laser light having a wavelength selected from a wavelength range of 700-1100 nm. A laser soldering method using a soldering device having a plurality of laser oscillators each capable of controlling an output, a plurality of optical fibers each connected to the plurality of laser oscillators and bundled together, and a condenser lens for condensing a laser beam which is a bundle of laser light emitted from an exit surface of the plurality of optical fibers, the method irradiating one soldering point with the laser beam condensed by the condenser lens to melt the solder supplied to the soldering point, thereby soldering a plurality of soldering points one by one in order, comprising:
The soldering point comprises an annular land and a rod-shaped lead inserted into a through hole of the land,
The arrangement pattern of the light output surfaces of the plurality of optical fibers is a pattern in which one light output surface located at the center is surrounded by other light output surfaces,
before or during soldering, by individually controlling the outputs of the plurality of laser oscillators, the intensities of the laser beams emitted from the plurality of optical fibers are individually adjusted according to the conditions of the portions to be irradiated with the respective laser beams ;
Thereby, a high-intensity laser beam is emitted from the light output surface located at the center to irradiate the lead, and a laser beam of a lower intensity is emitted from the other light output surfaces to irradiate the land, or a high-intensity laser beam is emitted from the other light output surfaces to irradiate the land, and a laser beam of a lower intensity is emitted from the light output surface located at the center to irradiate the lead.
A laser soldering method comprising the steps of: 6. The laser soldering method according to claim 5 , wherein the plurality of laser oscillators emit infrared laser light having a wavelength selected from the wavelength range of 700-1100 nm. 6. The laser soldering method according to claim 5, wherein the laser light emitted from the light exit surface located at the center of the arrangement pattern among the light exit surfaces of the plurality of optical fibers is visible laser light, and the laser light emitted from the other light exit surfaces is infrared laser light. 8. The laser soldering method according to claim 7, wherein the laser light emitted from the light exit surface located at the center of the arrangement pattern among the light exit surfaces of the plurality of optical fibers is a visible laser light having a wavelength selected from the wavelength range of 400-690 nm, and the laser light emitted from the other light exit surfaces is an infrared laser light having a wavelength selected from the wavelength range of 700-1100 nm.

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