Interdigitated Capacitive Touch Sensor Integrated in Laminated Glass with a Large Sensing Area

Abstract

In this paper, an interdigitated capacitive (IDC) touch sensor embedded in a laminated glass is proposed. The electrodes are sandwiched between two layers of glass in order to enhance the durability of the sensor structure. The proposed structure allows a large touch sensing area compared to the self-capacitance sensor. In addition, an IDC touch sensor is more immune to false detection compared to a self-capacitive sensor due to the well-defined sensing area with high electric field density. A study using electromagnetic simulation has been carried out to investigate the effect of thickness and type of glass on the performance of the touch sensor. Electrical properties including effective dielectric constant and loss tangent of different glass types are also considered in the simulation. The dimensions including IDC finger width, length and the gap between two electrodes are optimized for sensitivity of the touch sensor. The capacitance values while touching different areas of the sensor are also compared and ensured that the touch and non-touch states can be clearly differentiated independent of the touched area.