P‐40: Techniques of Touch Sensing and Display Driving for Avoiding Display Artifacts for Flexible OLED Applications

Currently, use of flexible OLED (Organic Light Emitting Diode) displays is increasing, especially in mobile phone applications due to the high flexibility in industrial design they provide for curved edge and foldable smartphones and tablets. For flexible OLED, TFE (Thin Film Encapsulation) technology is widely used to prevent water and oxygen permeation, and as the name suggests, it is extremely thin. Accordingly, when on‐cell touch panels transition from rigid OLED with ~200 um glass encapsulation to flexible OLED with ~8 um TFE, the distance between display electrodes and the touch sensor becomes considerably closer. The dramatically increased capacitive coupling between the display and touch systems produces a correspondingly increased risk of errors in voltages driven to the display pixels due to touch sensing modulation coupling into the display system, resulting in deteriorated display image quality. In this paper, we introduce touch sensing and display driving techniques for avoiding display artifacts for flexible OLED applications.