Optical touch screen device and related hand-writing system

摘要

An optical touch screen device includes a light output panel, a first polarizer, a first light-pervious plate, a liquid crystal layer and an image capture module. The light output panel includes a first surface for outputting light rays. The first polarizer is stacked on the first surface. The first light-pervious plate is arranged facing the first polarizer. The liquid crystal layer is arranged between the first polarizer and the first light-pervious plate. The liquid crystal layer includes a plurality of liquid crystal molecules aligned in predetermined orientations. The image capture module has a viewing field covering an entire surface of the first light-pervious plate. The image capture module includes a second polarizer. The second polarizer has a polarization axis associated thereof. The liquid crystal layer is configured for causing light transmitting therethrough to have a polarization direction perpendicular to the second polarization axis.