Invited paper: Hybrid transflective displays using vertically integrated transparent OLED and reflective LCD

We demonstrate a hybrid device by vertically integrating a reflective LCD and a transparent OLED. The vertical alignment (VA) LC cell operated at normally black (NB) mode is placed beneath the transparent OLED to improve device transmittance. Under dark ambient, OLED is the primary display but the NBRLCD absorbs the incoming light which in turn increases the ambient contrast ratio (A-CR). However, it also absorbs the photons from the OLED emission and decreases the efficiency. In our hybrid device, by placing the transparent OLED on top of the reflective LCD, the transmittance of the hybrid device is enhanced by 57.3% due to the asymmetric emission intensities from both sides of the transparent OLED. Under bright ambient conditions, the OLED could be washed out but the RLCD is activated. Hence, the tandem display exhibits a high contrast ratio (>105:1) under any ambient light conditions.