Patent ID: 8853590

Claim:
A device for irradiating a laser beam onto an amorphous silicon thin film formed on a substrate, the device comprising: a laser oscillator for generating the laser beam; a projection lens for focusing the laser beam onto the thin film; a reflector for reflecting the laser beam guided onto the thin film; a controller programmed to position the reflector so as to reflect the laser beam away from the thin film during a preheating of the projection lens before the temperature of the projection lens reaches a predetermined temperature, and to position the reflector so as to allow the focusing of the laser beam onto the thin film when the temperature of the projection lens reaches at least the predetermined temperature, so that the controller controls the reflector so as to selectively prevent exposure of the amorphous silicon thin film to the laser beam during the preheating of the projection lens to the predetermined temperature for the sequential lateral solidification process, and an absorber for absorbing the laser beam reflected by the reflector before the temperature of the projection lens reaches the predetermined temperature.