Patent ID: 7807944

Claim:
A laser processing apparatus for irradiating a work piece with a laser beam to process the irradiated portion comprising: a laser oscillator for generating said laser beam with a predetermined pulse; an irradiation position control optical system for causing said laser beam to irradiate a predetermined position on said work piece; a plurality of optical path systems for guiding the laser beam emitted from said laser oscillator to said irradiation position controlling optical system; and a total reflection mirror as an optical path switch, which is capable of proceeding into and retracting from an optical path, for determining which optical path system is used, from said plurality of optical path systems, wherein said plurality of optical path systems includes (1) at least a first optical path system that guides said laser beam emitted from said laser oscillator to said irradiation position control optical system without changing its energy distribution in the direction perpendicular to the optical axis of the laser beam and (2) a second optical path system that guides said laser beam emitted from said laser oscillator to said irradiation position control optical system while changing its energy distribution in the direction perpendicular to the optical axis of the laser beam, and said total reflection mirror moves into and retracts from the optical path during an off-time of the laser beam in the predetermined pulse of said laser oscillator such that said total reflection mirror begins being driven for the moving into and retracting from the optical path when the predetermined pulse of said laser beam changes to an off-state, and driving of said total reflection mirror for the moving into and retracting from the optical path is completed before the predetermined pulse of said laser beam changes to an on-state.