Laser processing device

Abstract

The invention provides a laser processing device. The laser processing device comprises a laser source, a polarization beam splitter, a first reflecting mirror, a second reflecting mirror, a polarization beam combiner and a focusing element, the laser source is used for generating laser, and the polarization beam splitter is used for splitting the laser into a first light beam and a second light beam with different polarization states. The first reflector is used for reflecting the first light beam, and the second reflector is used for reflecting the second light beam. The polarization light combiner is arranged on the path of the first light beam reflected by the first reflector and the path of the second light beam reflected by the second reflector, wherein the optical axis of the polarization light combiner is not parallel to the first light beam. The polarization light combiner is used for guiding the first light beam and the second light beam. The focusing element is arranged on the path of the first light beam and the second light beam guided by the polarization light combiner.

Description

Technical Field

[0001] The invention relates to a processing device, in particular to a laser processing device. Background Art

[0002] Among various processing devices, laser processing devices are capable of concentrating energy at a specific position, and this specific position may include a specific position in the horizontal direction and a specific depth position, thereby achieving precise processing of micro components (such as micro light emitting diodes).

[0003] Existing laser processing devices usually use a laser beam to process the object to be processed, and the laser source in the laser processing device can move relative to the supporting platform for the object to be processed, so as to process different positions of the object to be processed or different objects to be processed. However, when the object to be processed is processed by scanning the object to be processed with a laser beam, the processing time will be limited by the scanning speed of the laser beam, and it is difficult to shorten the processing time. Summary of the invention

[0004] The present invention is directed to a laser processing device which can effectively shorten the processing time.

[0005] One embodiment of the present invention provides a laser processing device, including a laser source, a polarizing beam splitter (PBS), a first reflector, a second reflector, a polarization beam combiner and a focusing element. The laser source is used to generate laser light, and the polarization beam splitter is used to split the laser light into a first beam and a second beam with different polarization states, wherein the first beam passes through the polarization beam splitter, and the second beam is reflected by the polarization beam splitter. The first reflector is used to reflect the first beam, and the second reflector is used to reflect the second beam. The polarization beam combiner is arranged on the path of the first beam reflected by the first reflector and on the path of the second beam reflected by the second reflector, wherein the optical axis of the polarization beam combiner is not parallel to the first beam. The polarization beam combiner is used to receive the first beam and the second beam, and guide the first beam and the second beam. The focusing element is arranged on the path of the first beam and the second beam guided by the polarization beam combiner, and is used to converge the first beam and the second beam and respectively form a first light spot and a second light spot separated from each other.

[0006] One embodiment of the present invention provides a laser processing device, including a laser source, a polarization beam splitter, a first reflector, a second reflector, a polarization beam combiner and a focusing element. The laser source is used to generate laser light, and the polarization beam splitter is used to split the laser light into a first light beam and a second light beam with different polarization states, wherein the first light beam passes through the polarization beam splitter, and the second light beam is reflected by the polarization beam splitter. The first reflector is used to reflect the first light beam, and the second reflector is used to reflect the second light beam. The polarization beam combiner is arranged on the path of the first light beam reflected by the first reflector and on the path of the second light beam reflected by the second reflector, wherein the optical axis of the polarization beam combiner is parallel to the first light beam, and the polarization beam combiner is used to receive the first light beam and the second light beam, and guide the first light beam and the second light beam. The focusing element is arranged on the path of the first light beam and the second light beam guided by the polarization beam combiner, and is used to converge the first light beam and the second light beam and respectively form a first light spot and a second light spot separated from each other, wherein the first reflector and the second reflector are arranged non-parallel to each other.

[0007] In the laser processing device of the embodiment of the present invention, since the optical axis of the polarization beam combiner is not parallel to the first light beam or the first reflector and the second reflector are not parallel to each other, the first light beam and the second light beam emitted from the polarization beam combiner will be emitted in different directions, and then be focused by the focusing element into the first light spot and the second light spot separated from each other. The first light spot and the second light spot can process different positions at the same time, so as to achieve the effect of doubling the working time. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of an optical path of a laser processing device according to an embodiment of the present invention;

[0009] Figure 2 for Figure 1 A cross-sectional schematic diagram of an embodiment of a polarization light combiner in FIG.

[0010] Figure 3 and Figure 4 The optical axis of the polarization light combiner is respectively shown to be deflected in two different directions relative to the first light beam;

[0011] Figure 5 for Figure 1 Schematic diagram of the partial optical path of the polarization light combiner and the focusing element;

[0012] Figure 6 A schematic diagram of an optical path of a laser processing device according to another embodiment of the present invention;

[0013] Figure 7 A schematic diagram of a partial optical path of a polarization beam combiner and a focusing element of a laser processing device according to another embodiment of the present invention;

[0014] Figure 8FIG. 4 is a schematic diagram of an optical path of a laser processing device according to another embodiment of the present invention. DETAILED DESCRIPTION

[0015] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0016] Figure 1 This is a schematic diagram of the optical path of a laser processing device according to an embodiment of the present invention. Figure 1 The laser processing device 100 of the present embodiment includes a laser source 110, a polarization beam splitter 120, a first reflector 130, a second reflector 140, a polarization beam combiner 150, and a focusing element 160. The laser source 110 is used to generate a laser 112, and the polarization beam splitter 120 is used to split the laser 112 into a first light beam 122 and a second light beam 124 having different polarization states, wherein the first light beam 122 penetrates the polarization beam splitter 120, and the second light beam 124 is reflected by the polarization beam splitter 120. In the present embodiment, the first light beam 122 has a first polarization direction P1, and the second light beam 124 has a second polarization direction P2, wherein the first polarization direction P1 is, for example, a P polarization direction, and the second polarization direction P2 is, for example, an S polarization direction.

[0017] The first reflector 130 is used to reflect the first light beam 122, and the second reflector 140 is used to reflect the second light beam 124. The polarization beam combiner 150 is disposed on the path of the first light beam 122 reflected by the first reflector 130 and on the path of the second light beam 124 reflected by the second reflector 140, wherein the optical axis A1 of the polarization beam combiner 150 is not parallel to the first light beam 122. The polarization beam combiner 150 is used to receive the first light beam 122 and the second light beam 124, and guide the first light beam 122 and the second light beam 124.

[0018] In this embodiment, the polarization beam combiner 150 is a polarization beam splitter having a polarization beam splitting surface 152. The first light beam 122 having a P polarization direction will penetrate the polarization beam splitting surface 152, while the second light beam 124 having an S polarization direction will be reflected by the polarization beam splitting surface 152. The optical axis A1 is defined as being 45 degrees from the normal line N1 of the polarization beam splitting surface 152 and falling on the plane where the first light beam 122 and the second light beam 124 are located (e.g. Figure 1 In one embodiment, as Figure 2As shown, the polarization splitting surface of the polarization light combiner 150 may be located between the two prisms 154 and 156, and the optical axis A1 is perpendicular to the surface 157 of the prism 156 that is opposite to the polarization splitting surface 152. In this embodiment, the first light beam 122 with a P polarization direction enters the prism 154 from the surface 159 and penetrates the polarization splitting surface 152 and then exits from the surface 157, and the second light beam 124 with an S polarization direction enters the prism 156 from the surface 158 and is reflected by the polarization splitting surface 152 and then exits from the surface 157, thereby forming a light combining effect.

[0019] The focusing element 160 is disposed on the paths of the first light beam 122 and the second light beam 124 guided by the polarization beam combiner 150 and is used to converge the first light beam 122 and the second light beam 124 to form a first light spot C1 and a second light spot C2 separated from each other. In this embodiment, the focusing element 160 is, for example, a lens.

[0020] In the laser processing device 100 of the present embodiment, since the optical axis A1 of the polarization light combiner 150 is not parallel to the first light beam 122, the first light beam 122 and the second light beam 124 emitted from the polarization light combiner 150 are emitted in different directions, and then are focused into the first light spot C1 and the second light spot C2 separated from each other by the focusing element 160. The first light spot C1 and the second light spot C2 can process different positions at the same time, so as to achieve the effect of doubling the working time.

[0021] Specifically, since the first light beam 122 can pass through the polarization light combiner 150, no matter whether the incident angle relative to the first light beam 122 is 45 degrees or other angles, the direction of the first light beam 122 before and after passing through the polarization light combiner 150 remains unchanged. In this embodiment, since the optical axis A1 is not parallel to the first light beam 122, the incident angle of the second light beam 124 to the polarization light combiner 150 (i.e., the incident angle to the polarization splitting surface 152) is greater than 45 degrees or less than 45 degrees. In this way, the reflection angle of the second light beam 124 reflected by the polarization light combiner 150 is also not 45 degrees, so that the first light beam 122 and the second light beam 124 are emitted in different directions when emitted from the polarization light combiner 150. That is to say, the polarization light combiner 150 guides the first light beam 122 and the second light beam 124 to the focusing element 160 in a first direction (i.e., the direction in which the first light beam 122 is emitted from the polarization light combiner) and a second direction (i.e., the direction in which the second light beam 124 is emitted from the polarization light combiner) with an angle, so that the first light beam 122 and the second light beam 124 are irradiated at different positions of the focusing element 160, thereby causing the focusing element 160 to converge into the first light spot C1 and the second light spot C2 at two different positions, respectively.

[0022] That is to say, in this embodiment, if Figure 3As shown, the optical axis A1 of the polarization light combiner 150 is deflected relative to the first light beam 122 about a rotation axis A2 , wherein the rotation axis A2 is perpendicular to the first light beam 122 and the second light beam 124 .

[0023] However, in another embodiment, if Figure 4 As shown, the optical axis A1 of the polarization light combiner 150 is deflected relative to the first light beam 122 with the second light beam 124 incident on the polarization light combiner 150 as the axis, so that the first light spot C1 and the second light spot C2 are at different positions. Figure 3 Separation in the other direction.

[0024] In this embodiment, the laser processing device 100 further includes a carrying platform 170 for carrying at least one micro light emitting element 50, wherein the first light spot C1 and the second light spot C2 fall on the micro light emitting element 50. The carrying platform 170 may carry one or more micro light emitting elements 50, and the first light spot C1 and the second light spot C2 may fall on different positions of the same micro light emitting element 50, or fall on two micro light emitting elements 50 respectively. In one embodiment, the micro light emitting element 50 is, for example, a micro light emitting diode, and the laser processing device 100 is a micro light emitting diode transfer device for peeling the micro light emitting diode from the carrier, and the distance D between the first light spot C1 and the second light spot C2 is less than 10 microns. In addition, in one embodiment, the focal depth of the first light spot C1 and the second light spot C2 formed by the focusing element 160 is greater than the height of the micro light emitting element 50, that is, the focal depth can cover all height positions of the micro light emitting element 50, and can also eliminate the influence of the height error, so that the energy density of the light spot will not be reduced too much due to not being in focus. In addition, since the first light beam 122 and the second light beam 124 are from the same laser 112, the first light beam 122 and the second light beam 124 can have the same or similar characteristics, and the processing effects formed on the object to be processed (such as the micro-light emitting element 50) can also be the same. Therefore, compared with the difference caused by using two laser sources to process two positions respectively, the laser processing device 100 of this embodiment can effectively reduce the processing difference between the two positions, that is, reduce the characteristic difference between the first light spot C1 and the second light spot C2.

[0025] In this embodiment, the optical axis A1 of the polarization light combiner 150 is deflected relative to the first light beam 122 so that the first light beam 122 and the second light beam 124 are emitted in different directions. This can reduce the positional offset of the light beam on the light path, and can reduce the volume and size of each optical element. Compared with the light path offset caused by deflecting the first reflector 130 or the second reflector 140, a larger polarization light combiner 150 is required to receive the first light beam 122 or the second light beam 124. In addition to saving costs, smaller-sized elements can also reduce the instability caused by temperature and assembly tolerance. In addition, in this way, the direction of the light beam can be changed at a position closer to the focusing element 150, and the range of the two light beams (i.e., the first light beam 122 and the second light beam 124) can be covered by a smaller focusing element at the same time.

[0026] In this embodiment, the laser processing device 100 further includes a first phase retarder 182, which is disposed on the path of the laser 112 and between the laser source 110 and the polarization beam splitter 120, and is used to change the ratio of the first light beam 122 and the second light beam 124 contained in the laser 112. Specifically, the first phase retarder 182 can rotate with the laser 112 as an axis. Since the laser 112 has a certain degree of polarization, rotating the first phase retarder 182 can change the polarization direction of the laser 112, thereby also changing the S polarization component and the P polarization component of the polarization direction, thereby changing the light intensity ratio of the first light beam 122 with the P polarization direction and the second light beam 124 with the S polarization direction 124.

[0027] In this embodiment, the laser processing device 100 further includes a second phase retarder 184, which is disposed on the second light path between the polarization beam splitter 120, the second reflector 140 and the polarization beam combiner 150, and is used to generate a phase difference for the second light beam 124. The second phase retarder 184 can be rotated with the second light beam 124 as the axis to transform the second polarization direction P2 (i.e., the S polarization direction) of the second light beam 124 into other polarization directions, which is equivalent to changing the S polarization component and the P polarization component of the second light beam 124, and the portion of the second light beam 124 with the S polarization direction can be reflected by the polarization beam combiner 150 to form a second light spot C2, while the portion of the second light beam 124 with the P polarization direction penetrates the polarization beam combiner 150 and becomes stray light. Therefore, as the second phase retarder 184 is rotated to change the S polarization component, the light intensity of the second light spot C2 can be adjusted. By rotating the first phase retarder 182 and the second phase retarder 184, the light intensities of the first light spot C1 and the second light spot C2 can be adjusted to any combination of light intensities, or can be adjusted to make the light intensities of the two light spots equal. Figure 1In the example, the second phase retarder 184 is configured between the polarization beam splitter 120 and the second reflector 140. However, in other embodiments, the second phase retarder 184 may also be configured between the second reflector 140 and the polarization beam combiner 150. In addition, in other embodiments, the first phase retarder 182 may not be used, but the laser source 110 may be rotated with the laser 112 as the axis, so that the polarization direction of the laser 112 can be changed, thereby changing the light intensity ratio of the first light beam 122 and the second light beam 124.

[0028] In this embodiment, the optical path length of the first light path between the polarization beam splitter 120, the first reflector 130 and the polarization light combiner 150 is the same as the optical path length of the second light path between the polarization beam splitter 120, the second reflector 140 and the polarization light combiner 150, so that there is no time difference in the formation time of the first light spot C1 and the second light spot C2.

[0029] Figure 5 for Figure 1 Schematic diagram of the partial optical path of the polarization beam combiner and focusing element. Please refer to Figure 1 and Figure 5 In this embodiment, the light receiving aperture W of the focusing element 160 is greater than the product of the angle θ1 between the first light beam 122 and the second light beam 124 and the light receiving distance L, where the light receiving distance L is the distance from the polarization light combiner 150 to the focusing element 160. In this way, both the first light beam 122 and the second light beam 124 can be received by the focusing element 160. In addition, in this embodiment, the distance D between the first light spot C1 and the second light spot C2 is greater than 2.44λ(f / #), where λ is the wavelength of the laser 112, and f / # is the aperture number of the focusing element 160. Since the lower limit of the size of the light spot depends on the diffraction limit, the size of the light spot is limited by the above conditions to be less than the distance D between the two light spots that are expected to be separated, so as to avoid the phenomenon of partial overlap of the two light spots. In addition, f / # is defined as BFL / W, where BFL is the back focal length of the focusing element 160, that is, the distance from the focusing element 160 to the first light spot C1 or the second light spot C2.

[0030] Figure 6 This is a schematic diagram of the optical path of a laser processing device according to another embodiment of the present invention. Figure 6 The laser processing device 100a of this embodiment is similar to Figure 1The laser processing device 100 of the embodiment is different from the laser processing device 100 of the embodiment. The main difference between the two is that the laser processing device 100a of the embodiment further includes a third phase retarder 186, which is disposed on the first light path between the polarization beam splitter 120, the first reflector 130 and the polarization beam combiner 150, and is used to generate a phase difference for the first light beam 122. The third phase retarder 186 can rotate with the first light beam 122 as the axis to transform the first polarization direction P1 (i.e., the P polarization direction) of the first light beam 122 into other polarization directions, which is equivalent to changing the S polarization component and the P polarization component of the first light beam 122, and the portion of the first light beam 122 with the P polarization direction can penetrate the polarization beam combiner 150 to form a first light spot C1, while the portion of the first light beam 122 with the S polarization direction is reflected by the polarization beam combiner 150 to form stray light. Therefore, as the third phase retarder 186 is rotated to change the P polarization component, the light intensity of the first light spot C1 can be adjusted. That is, by rotating the second phase retarder 184 and the third phase retarder 186 , the light intensities of the first light spot C1 and the second light spot C2 can be more easily adjusted to any light intensity combination, or can be well adjusted to have the light intensities of the two light spots equal.

[0031] exist Figure 6 In the embodiment, the third phase retarder 186 is disposed between the first reflector 130 and the polarization beam combiner 150 . However, in other embodiments, the third phase retarder 186 may also be disposed between the polarization beam splitter 120 and the first reflector 130 .

[0032] In the above embodiments, the first phase retarder 182, the second phase retarder 184 and the third phase retarder 186 can be half wave plates, quarter wave plates, eighth wave plates, other wave plates or combinations thereof, and can be formed of birefringent materials.

[0033] Figure 7 This is a partial optical path diagram of a polarization beam combiner and a focusing element of a laser processing device according to another embodiment of the present invention. Figure 7 , the local optical path of the laser processing device of this embodiment is similar to Figure 5 The main difference between the two is that in this embodiment, the focusing element 160b is a concave reflector, which focuses the first light beam 122 and the second light beam 124 into the first light spot C1 and the second light spot C2 respectively by reflection.

[0034] Figure 8 This is a schematic diagram of the optical path of a laser processing device according to another embodiment of the present invention. Figure 8 The laser processing device 100c of this embodiment is similar to Figure 1The main difference between the two is that in the laser processing device 100c of the present embodiment, the first reflector 130 and the second reflector 140 are arranged non-parallel to each other, so that the angle between the first light beam 122 and the second light beam 124 emitted from the polarization combiner 150 can be enlarged, thereby increasing the distance D between the first light spot C1 and the second light spot C2. In some embodiments, the optical axis of the polarization beam combiner 150 is parallel to the first light beam 122 before incidence, and the second reflector 140 is configured to be non-parallel to the first reflector 130, so that the direction of the second light beam 124 after being reflected by the polarization beam combiner 150 (i.e., the polarization splitting surface 152) is non-parallel to the first light beam 122, and then the focusing element 160 is used to converge the first light spot C1 and the second light spot C2 respectively. In this embodiment, the first light beam 122 and the second light beam 124 pass through the polarization beam splitter 120, the polarization beam combiner 150, and the first reflector 130 or the second reflector 140 for the same number of times, the loss caused by the above elements is equivalent, and the path length is also the same, which can reduce the energy difference between the first light spot C1 and the second light spot C2. In contrast, in Figure 1 In the laser processing device 100 , the first reflecting mirror 130 and the second reflecting mirror 140 may be disposed parallel to each other.

[0035] In summary, in the laser processing device of the embodiment of the present invention, since the optical axis of the polarization light combiner is not parallel to the first light beam or the first reflector and the second reflector are not parallel to each other, the first light beam and the second light beam emitted from the polarization light combiner will be emitted in different directions, and then be focused by the focusing element into the first light spot and the second light spot separated from each other. The first light spot and the second light spot can process different positions at the same time, so as to achieve the effect of doubling the working time.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser processing device, characterized in that: include: A laser source for generating laser light; A polarization beam splitter, used to split the laser into a first beam and a second beam having different polarization states, wherein the first beam penetrates the polarization beam splitter and the second beam is reflected by the polarization beam splitter; A first reflector, used to reflect the first light beam; A second reflector, used to reflect the second light beam; a polarization light combiner, disposed on a path of the first light beam reflected by the first reflector and on a path of the second light beam reflected by the second reflector, wherein an optical axis of the polarization light combiner is not parallel to the first light beam, and the polarization light combiner is used to receive the first light beam and the second light beam, and guide the first light beam and the second light beam; as well as The focusing element is disposed on the paths of the first light beam and the second light beam guided by the polarization light combiner, and is used for converging the first light beam and the second light beam to form a first light spot and a second light spot separated from each other.

2. The laser processing device according to claim 1, characterized in that: The optical axis of the polarization light combiner is deflected relative to the first light beam about a rotation axis, wherein the rotation axis is perpendicular to the first light beam and the second light beam.

3. The laser processing device according to claim 1, characterized in that: The optical axis of the polarization light combiner is deflected relative to the first light beam around the second light beam incident on the polarization light combiner.

4. The laser processing device according to claim 1, characterized in that: The polarization light combiner guides the first light beam and the second light beam to the focusing element in a first direction and a second direction with an included angle.

5. The laser processing device according to claim 1, characterized in that: The incident angle of the second light beam to the polarization light combiner is greater than 45 degrees or less than 45 degrees.

6. The laser processing device according to claim 1, characterized in that: The first reflector and the second reflector are arranged non-parallel to each other.

7. The laser processing device according to claim 1, characterized in that: It also includes a first phase delay plate, which is arranged on the path of the laser and located between the laser source and the polarization beam splitter, and is used to change the ratio of the first light beam and the second light beam contained in the laser.

8. The laser processing device according to claim 7, characterized in that: It also includes a second phase delay plate, which is arranged on the second light path between the polarization beam splitter, the second reflector and the polarization beam combiner, and is used to generate a phase difference for the second light beam.

9. The laser processing device according to claim 7, characterized in that: It also includes a third phase delay plate, which is arranged on the first light path between the polarization beam splitter, the first reflector and the polarization beam combiner, and is used to generate a phase difference for the first light beam.

10. The laser processing device according to claim 1, characterized in that: The optical path length of a first optical path between the polarization beam splitter, the first reflector, and the polarization light combiner is the same as the optical path length of a second optical path between the polarization beam splitter, the second reflector, and the polarization light combiner.

11. The laser processing device according to claim 1, characterized in that: The focusing element is a lens or a concave reflecting mirror.

12. The laser processing device according to claim 1, characterized in that: The laser processing device is a micro light emitting diode transfer device, and the distance between the first light spot and the second light spot is less than 10 microns.

13. The laser processing device according to claim 1, characterized in that: The device also includes a carrying platform for carrying at least one micro light emitting element, wherein the first light spot and the second light spot fall on the at least one micro light emitting element.

14. The laser processing device according to claim 13, characterized in that: The focal depths of the first light spot and the second light spot formed by the focusing element are greater than the height of the micro light emitting element.

15. The laser processing device according to claim 1, characterized in that: The light receiving aperture of the focusing element is larger than the product of the angle between the first light beam and the second light beam and the light receiving distance, and the light receiving distance is the distance from the polarization light combiner to the focusing element.

16. The laser processing device according to claim 1, characterized in that: The distance between the first light spot and the second light spot is greater than 2.44λ(f / #), where λ is the wavelength of the laser and f / # is the aperture number of the focusing element.

17. A laser processing device, characterized in that: include: A laser source for generating laser light; A polarization beam splitter, used to split the laser into a first beam and a second beam having different polarization states, wherein the first beam penetrates the polarization beam splitter and the second beam is reflected by the polarization beam splitter; A first reflector, used to reflect the first light beam; A second reflector, used to reflect the second light beam; a polarization light combiner, disposed on a path of the first light beam reflected by the first reflector and on a path of the second light beam reflected by the second reflector, wherein an optical axis of the polarization light combiner is parallel to the first light beam, and the polarization light combiner is used to receive the first light beam and the second light beam, and guide the first light beam and the second light beam; as well as A focusing element is disposed on the paths of the first light beam and the second light beam guided by the polarization light combiner, and is used to converge the first light beam and the second light beam to form a first light spot and a second light spot separated from each other, The first reflector and the second reflector are arranged non-parallel to each other.

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