| 摘要 |
<p>A system which determines the location of a stylus (14) relative to a screen (12). The screen (12) has a transparent plate that covers a liquid crystal display. Attached to the edges of the plate are transducers (24, 28) that create waves that propagate across the plate. An excitation circuit is connected to the transducers to coordinate and initiate the waves. The system also includes a stylus (14) that can be pressed against the plate by the user which detects the presence of the waves and sends a detection signal to a computation circuit, which determines the time for the wave to travel from the transducer to the stylus. The location of the stylus (14) relative to the plate is then computed by the computation circuit. The transducers may be arranged to produce waves that alternately travel on the x and y - axis of the plate. The plate may be constructed from a plurality of fibre optic elements. <IMAGE></p> |
