koordinatendatenausgabevorrichtung and flu00fcssigkristalltablettvorrichtung with high koordinatenmessgenauigkeit

摘要

A liquid crystal tablet equipment which allows improvement in accuracy of coordinate measurements by removing undesirable influence of noise caused by line pulse signals applied to a liquid crystal display and allows coordinate measurement in shorter time period includes a liquid crystal display (15), a liquid crystal display control circuit (14) for applying the line pulse signals at a prescribed interval to each of an array of pixels constituting the liquid crystal display (15), a tablet (17) stacked on the liquid crystal display (15), an A/D converter (18) receiving a coordinate signal output from the tablet (17), a tablet control circuit (16) for calculating coordinate data from a digital signal output from the A/D converter (18), and a CPU (11) for letting A/D converter (18) output the digital signal after a prescribed time period from a timing of activation of the line pulse signal. IMAGE