LCD and OLED displays take advantage of the thin film transistor performance to switch the display pixel matrix. Driver electronics, memory and CPU circuits can be directly produced on the glass substrate. Thin silicon films are transferred into the liquid phase and controlled solidification results in homogenous crystallization providing high electron/hole mobility.

Green laser light (515 nm, 532 nm) is well suited for annealing of thin a–Si films. The dynamic increase of the absorption in a-Si  film  (200,000 cm^-1) with temperature provides an efficient heating process over 50 nm thickness. Pulsed green laser radiation generates the process matching energy density in exposure intervals from 300 ns up to 1,200 ns.

A new alternative to near complete melt ELA (Excimer Laser Annealing) of thin Si-film is GLA (Green Laser Annealing). A Gaussian line beam of 750mm length and longer is created by using fiber coupled 532nm DPSSL of typically 60ns pulse length. This method allows to prepare equivalent ELA type LTPS (low temperature p-Si) films at dramatically reduced cost of ownership.

Prof James Im and coworkers from Columbia University published first results in the 90's (e.g. Robert S. Sposili, James S. Im, Sequential lateral solidification of thin silicon films on SiO₂, Applied Physics Letters 69, p. 2864 (1996)) and several procedure patents were filed.

Applying continuous wave (cw) 532 nm laser radiation by fast line beam scanning gives access to process duration from 10-50 μs. The full melt crystallization allows to prepare nearly single crystal film performance but the heat transfer into the glass requires designs which compensate thermal stress (glass type, additional protection layers).

The power density can be reduced to control the temperature of the film below the Si-melting temperature and initiate solid phase crystallization (SPC). Although the mobility of the electrons is just increased by a factor of 10-20 these Si-films have a great importance for future OLED-TV applications.