Tuneable Uv Solid-State Laser Lines For Surface Processing

Long UV laser lines find application in crystallization of Si, lift-off of flexible OLED displays from assistance glass and other surface processing technologies. With the appearance of powerful and reliable pulsed UV DPSS lasers in the last years, many efforts are directed to the implementation of such lasers in the line systems instead of excimer lasers. For the processing with a high energy density, several DPSS lasers have usually to be coupled in a homogeneous line focus with 100 - 1000 mm length and FWHM of 20 - 40 mu m. We describe an advantageous line design approach based on anisotropic laser beam transformation, which improves beam quality for the narrow line axis and allows tight focusing with large depth of the focus. Solutions for tuning the line width are discussed.