Patent ID: 9186749
Filing Date: 2015-11-17
Classification: B23K

Abstract:
1. A laser processing apparatus comprising: a chuck table for holding a workpiece; laser beam applying means for applying a laser beam to the workpiece held on the chuck table, the laser beam applying means including laser beam oscillating means for oscillating a laser beam, focusing means for focusing the laser beam oscillated by the laser beam oscillating means and applying the laser beam focused to the workpiece held on the chuck table, and a laser beam branching mechanism provided between the laser beam oscillating means and the focusing means for branching the laser beam oscillated by the laser beam oscillating means into a plurality of laser beams; and feeding means for relatively moving the chuck table and the laser beam applying means in a feeding direction; the laser beam branching mechanism including spread angle adjusting means for adjusting the spread angle of the laser beam oscillated by the laser beam oscillating means and a branching unit for branching the laser beam passed through the spread angle adjusting means into the plurality of laser beams; the branching unit including a half-wave plate, a first polarization beam splitter for separating the laser beam passed through the half-wave plate into P polarized light and S polarized light, a first mirror for reflecting the P polarized light obtained by the first polarization beam splitter, a second mirror for reflecting the S polarized light obtained by the first polarization beam splitter, and a second polarization beam splitter for leading the P polarized light reflected by the first mirror and the S polarized light reflected by the second mirror to different optical paths extending in the same direction; the first mirror and the second mirror being arranged so that the P polarized light and the S polarized light traveling in the same direction from the second polarization beam splitter are spaced a slight distance from each other; whereby the spread angle of the laser beam oscillated by the laser beam oscillating means is adjusted by the spread angle adjusting means to thereby adjust the spacing between the focal points of the plurality of laser beams formed by the P polarized light and the S polarized light to be focused by the focusing means.