Micromachining of assembled liquid crystal displays

Abstract

Lasers have come into wide use for the repair of liquid crystal displays (LCDs). As displays have become larger, more complex and thus increasingly more expensive, repair has become indispensable. Lasers are used to remove the ‘short’ (unwanted materials) as a form of laser repair. Currently, there are many lasers being used for this application, but they are not able to perform the process efficiently. Green yttrium aluminium garnet (YAG) and xenon lasers are not capable of removing indium tin oxide (ITO) in thin-film transistor (TFT) LCDs. Excimer lasers are capable of removing the ITO, but due to their opacity to glass substrates, the removal of the materials is not possible once the LCD is assembled. Therefore, there is a need to study another laser-based micromachining technique to remove the ITO in the assembled LCD. With the unique features of the ultrafast lasers, the femtosecond laser is introduced in this work to perform micromachining of ITO in the assembled LCD. The results clearly show that a femtosecond laser beam is able to penetrate through the glass substrate and polarizer to remove the ITO without damaging the LCD panel.