| 摘要 |
A laser processing apparatus including a pulsed laser oscillator for oscillating a pulsed laser beam, a focusing objective lens for focusing the pulsed laser beam, and a varifocal lens provided between the pulsed laser oscillator and the focusing objective lens. The varifocal lens has a piezoelectric device to change its focal length according to the period of radio-frequency waves produced by the piezoelectric device. A repetition frequency adjusting unit is connected to the pulsed laser oscillator, and a radio-frequency current frequency adjusting unit is connected to the piezoelectric device. The laser processing apparatus further includes a controller for controlling the repetition frequency adjusting unit and the radio-frequency current frequency adjusting unit so as to produce a phase difference between the repetition frequency of the pulsed laser beam and the frequency of the radio-frequency current to be applied to the piezoelectric device of the varifocal lens. |
