| CPC B23K 26/0643 (2013.01) [B23K 26/0624 (2015.10); B23K 26/0648 (2013.01); B23K 26/352 (2015.10); G02B 5/10 (2013.01); G02B 17/0808 (2013.01); G02B 19/0028 (2013.01); G02B 26/101 (2013.01); G02B 26/105 (2013.01)] | 20 Claims |
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1. A laser processing apparatus comprising:
a light source generating a first laser beam, a second laser beam, and a third laser beam; and
a light converging unit converging the first laser beam, the second laser beam, and the third laser beam to a first focal point, a second focal point, and a third focal point, respectively, in a plane perpendicular to a traveling direction of the first laser beam, wherein the first focal point is located in a central activation region and the second focal point and the third focal point are located in a peripheral activation region that surrounds the central activation region in the plane and are located on opposite sides of the first focal point in the plane,
wherein the light converging unit includes:
a first optical element including a through hole penetrating the first optical element;
a second optical element located after the first optical element in the traveling direction of the first laser beam and comprising a convex upper surface, a concave lower surface, and a central focusing hole aligned with the through hole of the first optical element, wherein the first laser beam passes through the through hole and the central focusing hole in a straight path from the first optical element to the central activation region, wherein the convex upper surface has a first radius of curvature and the concave lower surface has a second radius of curvature that is different from the first radius of curvature, wherein the convex upper surface includes a first region surrounding the central focusing hole in a plan view and reflecting the second laser beam and the third laser beam, and wherein the convex upper surface includes a second region surrounding the first region in the plan view and transmitting the reflected second and third laser beams; and
a third optical element located after the second optical element in the traveling direction of the first laser beam and comprising a focusing lens that focuses the first laser beam on to the first focal point after the laser beam passes through the central focusing hole and a third region surrounding the focusing lens in the plan view, wherein the second laser beam and the third laser beam pass through the third region,
wherein the light converging unit is configured to cause the first laser beam to pass through the central focusing hole and to converge at the first focal point, and
wherein the light converging unit is further configured to cause the second laser beam and the third laser beam to be reflected from the first region of the second optical element, then reflected from a lower surface of the first optical element, and then transmitted through the second region of the second optical element to converge at the second focal point and the third focal point, respectively.
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