14‐3: Capacitive and Inductive Hybrid (Inductive‐Inductive and Capacitive, LLC) Touch Sensor for Large‐Area Bottom‐Emission OLED Displays

This paper introduces a novel in‐cell capacitive and inductive hybrid (inductive‐inductive and capacitive, LLC) sensor for large‐area bottom‐emission organic light‐emitting diode (OLED) displays. The proposed LLC sensor consists of an LC sensor and a readout coil distributed across multiple layers in OLED structure. By leveraging inductive coupling between layers, the LLC sensor overcomes the electric field shielding effects caused by thick OLED cathode layers, enabling effective touch detection without compromising electrical stability. A 5x5 LLC sensor array was fabricated on a PCB, emulating the architecture of a bottom‐emission OLED display. Experimental evaluations demonstrate robust touch state recognition, with root mean square (RMS) output voltage differences ranging from 0.805 mV to 0.481 mV between touched and untouched sensors. The proposed LLC sensor retains the cost efficiency and design benefits of bottom‐emission OLEDs while addressing the limitations of conventional capacitive systems.