US Patent 7714251 Laser irradiation apparatus

Since the size of a plate for issuing gas used for a conventional laser irradiation apparatus is large and the distance between an optical system through which a laser light lastly passes and the plate is not enough, it is difficult to check the state of laser light delivered from the optical system which the laser light lastly passes through. A laser irradiation apparatus includes a laser oscillator, an optical system shaping laser light produced by the laser oscillator, a plate having an opening for issuing a gas, a stage provided below the blower, means for maintaining a constant distance between the blower and the stage above the stage, and means provided between the optical system and the blower for observing the laser light transmitted through the optical system are provided.