A Continuous-Grain Silicon-System LCD With Optical Input Function

In this paper, we describe a continuous-grain silicon-system LCD with integrated optical input function for application in next-generation mobile devices. The optical input function, which may be used for touch input or fingerprint-recognition applications, is achieved by integrating image-sensor elements within each display pixel. By using a one-transistor (1T) active pixel sensor, we have successfully integrated a 30 Hz, 300 dpi VGA image sensor within an LCD panel with an aperture ratio of 40%. Power consumption and circuit area in the panel are minimized through the use of a source driver circuit which combines the functions of both display and sensor.