Laser damage characteristics of indium-tin-oxide film and polyimide film irradiated by 1064nm high power lasers

The damage characteristics of the indium-tin-oxide (ITO) layer and the polyimide (PI) layer, which are two constituent components of a LCD, induced by a high-peak-power laser and a high-average-power laser are investigated. The PI alignment layer is pinned on the ITO film to imitate the structure of the LCD as much as possible in our study. Under the irradiation of the high-peak-power laser, the damage process of the PI/ITO/SUB sample involves thermally induced plastic deformation, followed by cooling when the irradiation fluence is near the LIDT, and rupture when the irradiation fluence is higher. High-average-power laser irradiation results in damaged morphologies of the bulge for the PI/ITO/SUB sample. The temperature distributions induced by the pulsed laser and the high-repetition-rate laser are investigated. The damage is attributed to the intrinsic heat absorption of the ITO films. Under the irritation of the high-peak-power laser, the temperature rises rapidly to a high degree at very short time because of the instant strong absorption in ITO layer, and resulted in vaporization of ITO layer consequently. Subsequently, the vaporized ITO breaks through the surface PI and develops the visible damage. However, under the irritation of high-average-power laser, ITO layer absorbs laser energy, resulting in a slow temperature rise and a small temperature gradient.