Sony gives more details about their 4.1" rollable OLED

Sony demonstrated a beautiful 4.1" flexible-rollable OLED display at SID - with 423x240 resolution (121ppi), 16.8 million colors and a 1000:1 contrast ratio. It's only 80um thick. Today the company revealed some more technical details.

Sony said that the most distinctive technological feature of the panel is the organic semiconductor material "PXX (peri-Xanthenoxanthene) derivative," which Sony developed. The OTFT has a carrier mobility of 0.4cm²/Vs (four times higher than that of pentacene, which is commonly used). As a result, it became possible to use organic TFTs to form a gate-driver circuit on a resin substrate. Because there is no need to embed a driver chip, the entire panel can be folded. Sony did however embed a driver chip (it isn't easy to form a source driver circuit on a resin substrate) - and so the OLED on display can be folded only to one side.

The Panel is 80um thick: 20um for the resin substrate, 35um for the OTFT and OLED and 25um for the resin cover. The PXX derivative and the electrode materials are made by a vacuum process while other insulating films are formed by a solution process at a temperature of 180°C or less. The luminance efficiency of the OLED device was enhanced by using gold (Au), which has a high work function, for the source/drain electrode.

In regard to the durability, when the panel was rolled around a cylinder with a curvature radius of 4mm 100,000 times with its resin cover (screen side) facing up, the properties of the TFT and the display capabilities such as the gamma characteristic and the brightness did not change, Sony said.