JP7744017B2 - Twin beam soldering equipment - Google Patents

Description

The present invention relates to a twin-beam soldering device that splits laser light into twin beams, allowing soldering at two locations in one go.

Patent Document 1 (JP 2013-203052 A) discloses a method for sealing a container and a lid by laser welding, using a rectangular beam with a uniform intensity distribution.

Patent Document 2 (JP 2007-110064 A) discloses a laser annealing method performed by irradiating a semiconductor film formed on the surface of a substrate with a laser beam, which includes a step of generating a linearly polarized rectangular laser beam whose cross section perpendicular to the direction of propagation is rectangular and whose electric field is oriented in the direction of the long side of the rectangle, or an elliptically polarized rectangular laser beam whose major axis is oriented in the direction of the long side.

Patent document 3 (JP 2001-23920 A) discloses that the divergence optical system 71 and telescope optical system 72 prevent differences in focus position, beam size, and uniformity from occurring in the rectangular beam formed by the homogenizer 41 due to the beam characteristics or differences between the first beam LB1 and the second beam LB2.

Patent Document 4 (JP Patent Publication No. 3-47690) discloses a laser processing robot that guides laser light by moving an arm and irradiates it onto the surface of a workpiece to perform processing. The robot includes a cylinder mounted within the arm, with a hole with a rectangular cross section penetrating the center and treated so that the laser light reflects off the surface of the hole with sufficiently small reflection loss; a convex lens mounted near one end of the cylinder; and a collimator lens mounted near the other end of the cylinder. Laser light in a non-rectangular beam mode is focused by the convex lens and incident on one end of the cylinder, where it is reflected a predetermined number of times within the cylinder before being emitted through the collimator lens, thereby being converted into laser light in a rectangular beam mode.

JP 2013-203052 A Japanese Patent Application Laid-Open No. 2007-110064 Japanese Patent Application Laid-Open No. 2001-23920 Japanese Patent Application Publication No. 3-47690

As electronic components become smaller, there has been an increasing demand for laser soldering devices that can heat weld areas with pinpoint accuracy. In such laser soldering devices, the object (solder material, component, board) irradiated with laser light absorbs the light, generating heat, and soldering is performed by raising the temperature to the required temperature, for example, 300°C. In the case of small electronic components, the soldering points are close together, so the temperature of the small electronic component rises when one is soldered, and then the temperature of the other component rises even further, which can cause problems with the soldering of one of the components that has been cut and soldered.

For this reason, the applicant proposed in Japanese Patent Application No. 2021-074631 a laser soldering device that can solder both terminals of a small electronic component at the same time using twin beams.

The applicant also discovered that because the soldering locations on small electronic components are square and the output distribution of rectangular laser light is a flat-top distribution, rectangular laser light is more suitable for soldering work than conventional circular laser light.

Furthermore, when using rectangular laser light, unlike circular laser light, it is desirable to be able to adjust the spacing, inclination, position, etc.

For this reason, the present invention provides a twin-beam soldering device that uses a pair of rectangular lasers and that allows for easy adjustment of the spacing, inclination, position, heat balance, etc. of the twin beams.

The present invention relates to a twin-beam soldering device that includes at least a fiber core that has a fiber core axis in the axial direction and emits a rectangular beam centered on the fiber core axis, a splitting prism that splits the rectangular beam emitted from the fiber core by having its prism ridge line facing the fiber core axis, and an optical lens that focuses the pair of rectangular beams split by the splitting prism at a predetermined position, wherein the splitting prism is movable in the axial direction of the fiber core axis.

This allows the splitting prism to move in the axial direction of the fiber core axis, thereby changing the spacing between the pair of rectangular beams.

It is also preferable that the split prism be movable in a direction perpendicular to the fiber core axis. This allows the prism ridgeline to be displaced relative to the fiber core axis, thereby changing the laser light intensity of each of the pair of rectangular beams and responding to changes in the heat capacity of the soldering location.

Furthermore, it is preferable that the fiber core be rotatable around a fiber core axis extending in the axial direction of the fiber core, thereby allowing each of the pair of rectangular beams to be tilted at a predetermined angle.

Furthermore, it is preferable that the splitting prism be rotatable around the fiber core axis, thereby allowing the positions of the pair of rectangular beams to be changed relative to the fiber core axis.

In this way, the present invention makes it possible to optically change the spacing, inclination, relative position, and thermal balance of a pair of rectangular beams, thereby making it possible to provide versatility for soldering operations.

As explained above, this invention makes it possible to easily change the optical direction of a pair of rectangular beams, thereby enabling soldering of small electronic components easily and reliably, thereby improving the efficiency of soldering work.

FIG. 1 is a schematic explanatory diagram showing an example of adjusting the spacing between a pair of rectangular beams of a twin-beam soldering device according to an embodiment of the present invention, where (a) shows an example of widening the spacing and (b) shows an example of narrowing the spacing. FIG. 2 is a schematic diagram showing an example of adjusting the heat quantity of a pair of rectangular beams of a twin beam soldering device according to an embodiment of the present invention, where (a) shows an example of equalizing the heat quantity of one rectangular beam, and (b) shows an example of increasing the heat quantity on one side and decreasing the heat quantity on the other side. FIG. 3 is an explanatory diagram showing the state of soldering an electronic component using a pair of rectangular beams, where (a) shows the case where the rectangular beam emission port of the fiber core is normal, and (b) shows an example of soldering in that case. Figure 4 is an explanatory diagram showing the state of soldering electronic components using a pair of rectangular beams, where (a) shows the state in which the rectangular beam emission port of the fiber core is inclined at 45°, and (b) is an explanatory diagram showing an example of soldering in that case. Figure 5 is an explanatory diagram showing the state of soldering an electronic component using a pair of rectangular beams, where (a) shows the state in which the rectangular beam emission port of the fiber core is inclined by 90 degrees, and (b) is an explanatory diagram showing the soldering state in that case. 6A and 6B are explanatory diagrams showing the prism ridges of the split prisms in their normal state, where FIG. 6A is an explanatory diagram showing the state of the split prisms, and FIG. 6B is an explanatory diagram showing an example of soldering in that case. Figure 7 is an explanatory diagram showing a state in which the prism ridge line of the split prism is inclined at 45 degrees, where (a) is an explanatory diagram showing the inclined state of the split prism, and (b) is an explanatory diagram showing an example of soldering in that case. Figure 8 is an explanatory diagram showing the state in which the prism ridge line of the split prism is inclined by 90 degrees, where (a) is an explanatory diagram showing the state in which the split prism is rotated by 90 degrees, and (b) is an explanatory diagram showing an example of soldering in that case.

The following describes an embodiment of the present invention with reference to the drawings.

1 and 2, the twin beam soldering device 1 of the present invention comprises at least a fiber core 3 having a fiber core axis A in the axial direction and emitting a rectangular beam 2 centered on the fiber core axis A; a splitter prism 5 having a prism ridge 4 facing the fiber core axis A to split the rectangular beam 2 emitted from the fiber core 3 into a pair of rectangular beams 2A and 2B; and an optical lens 6 that focuses the pair of rectangular beams 2A and 2B split by the splitter prism 5 at predetermined positions. While the splitter prism 5 and optical lens 6 are shown as separate units in the drawings in this embodiment, it is preferable that the splitter prism 5 and optical lens 6 be composed of multiple optical components. Essentially, the splitter prism 5 is structured to split the rectangular beam 2 onto one side and the other of the prism ridge 4, and the optical lens 6 is structured to focus each of the pair of split rectangular beams 2A and 2B at predetermined positions. These structures are well known to those skilled in the art, and therefore are shown as separate units in the drawings. In addition, the laser beam emission port 3A of the fiber core 3 is formed in a rectangular shape, allowing a rectangular beam 2 to be emitted.

The pair of rectangular beams 2A, 2B are focused on the soldering locations (terminals of the small electronic component 7) 8A, 8B of the small electronic component 7, heating each of the wiring terminals 10, 11 provided on the substrate 9 and soldering the terminals 8A, 8B of the small electronic component 7 to the wiring terminals 10, 11.

As shown in Figures 1(a) and (b), the splitting prism 5 is designed to be movable relative to the fiber core 3 (movable along its central axis extending in the longitudinal direction of the fiber core, or along the central axis of the fiber core).

When the splitting prism 5 is changed from the state shown in Figure 1(a) to the state shown in Figure 1(b), i.e., when the splitting prism 5 is moved toward the fiber core 3, the width of the rectangular beam 2 passing on both sides of the prism ridge 4 of the splitting prism 5 can be narrowed in the state shown in Figure 1(b) compared to the state shown in Figure 1(a), and therefore the respective focusing positions of the pair of rectangular beams 2A, 2B split by the splitting prism 5 by the optical lens 6 can be narrowed.

Figure 2(b) shows the split prism 5, which was in the position shown in Figure 1(a), shifted perpendicular to the fiber core axis A, for example, to the right in the figure. This shifts the prism ridge 4 of the split prism 5 from the fiber core axis A, allowing the laser light intensity of the rectangular beam 2A on one side (left side of the figure) to be greater than the laser light intensity of the rectangular beam 2B on the other side (right side of the figure). This allows the heat quantity of the soldered portion 8A (one terminal of the small electronic component) soldered by the rectangular beam 2A on one side to be greater than the heat quantity of the soldered portion 8B (the other terminal of the small electronic component) soldered by the rectangular beam 2B on the other side. This makes it possible to accommodate, for example, differences in heat capacity between the terminals 8A and 8B of the small electronic component and the wiring 10 and 11 on the board 9 and the soldered portion, thereby adjusting the heat balance.

Furthermore, the fiber core 3 is designed to be rotatable around the fiber core axis A. Figure 3(a) shows the case where the irradiation port 3A of the fiber core 3 is in the normal position. This allows a pair of rectangular beams 2A, 2B to be efficiently focused on the soldered points between the terminals 8A, 8B of the small electronic component 7 and the wiring 10, 11, as shown in Figure 3(b), for example.

Figure 4(a) shows the state in which the fiber core 3 has been rotated by 45°. As a result, as shown in Figure 4(b), the pair of rectangular beams 2A and 2B can be focused at the soldering point with a 45° inclination.

Figure 5(a) shows the state in which the fiber core 3 has been rotated by 90°. As a result, as shown in Figure 4(b), the pair of rectangular beams 2A and 2B can be focused at the soldering location while tilted by 90° (perpendicular to the state in Figure 3).

The splitter prism 5 is also designed to be rotatable around the fiber core axis A. Figure 6(a) shows the splitter prism 5 in its normal state, which allows the pair of rectangular beams 2A and 2B to be efficiently focused on the soldered points between the terminals 8A and 8B of the small electronic component 7 and the wiring 10 and 11, as shown in Figure 6(b), for example.

When the splitter prism 5 is rotated 45° from the state shown in Figure 6 to the state shown in Figure 7(a), the focusing positions of the pair of rectangular beams 2A, 2B can be shifted by 45° while maintaining the shape of the rectangular beams 2A, 2B, as shown in Figure 7(b).

Furthermore, when the splitter prism is rotated an additional 45° from the state shown in Figure 7(a), that is, when it is rotated 90° from the state shown in Figure 6(a), the focusing position of the pair of rectangular beams 2A, 2B can be moved from the vertical position shown in Figure 6(a) to the horizontal position shown in Figure 8(b).

As described above, the twin beam soldering device 1 according to the present invention can optically change the spacing, heat balance, tilt, and relative position of the focused positions of the pair of rectangular beams 2A and 2B, thereby making it versatile for soldering work.

REFERENCE SIGNS LIST 1 Twin beam soldering device 2, 2A, 2B Rectangular beam 3 Fiber core 3A Radiation port 4 Prism ridge 5 Split prism 6 Optical lens 7 Small electronic component 8A, 8B Terminal (soldering point)
9 Substrate 10, 11 Wiring A Fiber core axis

Claims (1)

A twin beam soldering device comprising at least a fiber core having a fiber core axis in the axial direction and emitting a rectangular beam centered on the fiber core axis, a splitting prism having a prism ridgeline facing the fiber core axis to split the rectangular beam emitted from the fiber core into a pair of rectangular beams, and an optical lens that focuses the pair of rectangular beams split by the splitting prism at predetermined positions,
The splitting prism is movable in the axial direction of the fiber core axis, and the splitting prism is movable in the direction perpendicular to the fiber core axis, and the splitting prism is rotatable around the fiber core axis, and
A twin beam soldering apparatus, wherein the fiber core is rotatable about a fiber core axis extending in the axial direction of the fiber core.