Laser processing machine

A laser processing machine comprising:

• a holding table that holds a workpiece thereon;
• a laser beam application unit that applies processing to the workpiece by focusing and applying a pulsed laser beam to the workpiece held on the holding table;
• and
• a moving unit that relatively moves the holding table and a focal point of the laser beam,
• wherein the laser beam application unit includes:
• a laser oscillator that emits the laser beam,
• an fθ main lens that focuses and applies the laser beam which has been emitted from the laser oscillator, to the workpiece held on the holding table, wherein the fθ main lens defines a front focal point and a back focal point,
• a scan unit that is arranged on an optical path between the laser oscillator and the fθ main lens, scans the laser beam, and guides the resulting scanned laser beam to the fθ main lens, and
• an fθ sub-lens that is arranged on the optical path between the laser oscillator and the scan unit and converts the laser beam from parallel light into diffused light, and
• wherein the scan unit includes a scan mirror with a reflecting surface on which the laser beam is incident from the fθ sub-lens, and the front focal point of the fθ main lens is positioned on the reflecting surface of the scan mirror, and
• further wherein a distance between the focal point of the laser beam, that has passed through the fθ main lens, at a processing point on the workpiece and the fθ main lens is greater than a distance between the back focal point of the fθ main lens and the fθ main lens, and wherein a distance between the front focal point of the fθ main lens and the fθ main lens is greater than a distance between the back focal point of the fθ main lens and the fθ main lens.