| 摘要 |
<p>The purpose of the present invention is to provide a laser machining apparatus which is easy to control gaps among multiple converging spots (converging points) of multiple branching-off laser beams. A laser beam irradiation device irradiating a workpiece, which is kept on a chuck table, with laser beams comprises: a laser oscillator; a converging unit; a laser beam branching-off unit arranged in between the laser oscillator and the converging unit. The laser beam branching-off unit includes: a 1/2 wavelength plate; a first polarization beam splitter dividing a laser beam, which passes through the 1/2 wavelength plate, into P polarization and S polarization; a first mirror reflecting the P polarization separated from the first polarization beam splitter; a second mirror reflecting the S polarization separated from the first polarization beam splitter; a second polarization splitter guiding the P and S polarizations reflected from the first and second mirrors toward optical paths in the identical direction; a branching-off unit provided with an angle adjustment means adjusting the angle for sending at least one between the P and S polarizations, which are reflected from the first and second mirror, into the second polarization splitter, wherein the angle adjustment means adjusts the angles for sending the P and S polarizations, which are reflected from the first and second mirrors, into the second polarization splitter for controlling the gaps of the converging points of the multiple laser beams.</p> |
