Toshiba developed a 11.7-inch flexible OLED panel

The developed product has a pixel of 960 × 540 and a resolution of 94 ppi, and is driven by an oxide semiconductor amorphous IGZO TFT. A combination of a white OLED material and an RGB three-color color filter (CF) enables color display. The OLED element is configured to be a bottom emission type that extracts light from the TFT substrate. The panel has an aperture ratio of 42%.

The fabrication process is to form an amorphous IGZO TFT by vacuum film formation and photolithography after coating polyimide (PI) having a thickness of about 10 μm on a glass substrate; then forming a color filter and a white OLED on the TFT array. Finally, the glass substrate is peeled off to form a flexible panel. Toshiba said, "It is the easiest to achieve mass production and large screen."

The amorphous IGZO TFT is a bottom gate type in which an etching stopper layer is provided on the upper portion of the semiconductor layer. In order to improve the reliability, after the etching stopper layer and the source/drain electrodes are formed, an annealing treatment of 300 ° C or less is added. The carrier mobility was 17.3 cm 2 /Vs, the threshold voltage was 0.86 V, and the Subthreshold Swing was 0.21 V/dec.

In addition, Toshiba has introduced an intuitive user interface (UI) that combines this development with a sensor to operate through a curved display section. Thus, the flexible panel not only has the characteristics of light weight and flexibility, but also "provides new added value" (the company). The demo shows the actual scenario of zooming in or out of the map app by slightly bending the panel.