AMOLED panel driven by OTFTs on polyethylene fabric substrate

Abstract In this study, AMOLED display panel was fabricated on polyethylene (PET) fabric substrate. By considering flexibility of the PET fabric, organic thin film transistors (OTFTs), which used TIPS-pentacene as the active layer material, were adopted as the driving devices for the OLEDs. A standard pixel circuit was employed using two OTFTs and one capacitor and one OLED. The panel specifications were as follows; a pixel pitch of 1.5 × 1.5 mm, a resolution of 32 × 32, an aperture ratio of 22%, and a diagonal length of 2.7 inches. The large surface roughness of the PET fabric could be reduced down to 0.3 μm from the initial roughness of 10 μm by coating polyurethane and photo-acrylic with a two-step process. On the smoothened fabric, the OTFTs and OLEDs were integrated into the pixel array through the key processes, the self-patterning of the gate dielectric of the OTFTs and the patterning of the TIPS-pentacene layer. The mobility of two OTFTs was 0.23 and 0.34 cm 2 /V∙sec in the pixel array, respectively, and the luminance of the OLED was 64,459 cd/m 2 . The AMOLED panel successfully operated to vary the luminance of each pixel according to the applied voltages.