US Patent 9536551 Laser processing method and apparatus

A laser processing method processes spots on an object in a scan area with a laser beam emitted from a laser emitter. The method includes steps of covering the scan area in such a way as to transmit the laser beam and define a closed space over the scan area, jetting an inert gas into the closed space so that the jetted inert gas forms a gas curtain sweeping along the scan area in the closed space, and discharging the inert gas from the closed space while maintaining a positive pressure in the closed space, thereby removing plumes from the spots processed with the laser beam and preventing the spots from oxidizing. The method is capable of stably laser-processing the object without changing the color of the processed spots.