Digitizing tablet and indicatory one somatotype digitizing tablet

摘要

PURPOSE: To improve the coordinate detection precision by providing a means which generates a correction voltage for canceling a voltage induced at an electrode positioned on an upper side owing to a scanning voltage impressed to an electrode positioned on a lower side distant from a detection pen. ;CONSTITUTION: When an (x)-coordinate detection period wherein segment electrode X positioned on the lower side are scanned is entered, a correction signal generating circuit 4 reads correction data out of an internal memory and sends it out as a correction signal to a correction voltage generating circuit 5. The correction voltage generating circuit 5 converts the correction signal from the correction signal generating circuit 4 from digital to analog and superposes it on the bias voltage V₁ from a DC power circuit 6 to obtain the correction voltage V₁'. Thus, the voltage induced at the common electrode Y owing to the scanning voltage V₅ which is impressed to the segment electrode X is canceled to prevent an induced noise from being detected by the detection electrode of a detection pen. Consequently, the coordinate detection precision can be improved.;COPYRIGHT: (C)1994,JPO&Japio