| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize stable coordinate detection with less litter and high detection precision while maintaining display performance by connecting second and third band amplification means, where frequencies are not overlapped, and detecting a Y-coordinate signal based on a signal component obtained by the third band amplification means. SOLUTION: A first gate means 21 extracts a very low voltage induced by a coordinate detection pulse added to a raw electrode scanning signal with a signal voltage induced by the detection electrode of an electronic pen 6 during a display period. Then, a second band amplification means 22 and a third band amplification means 23, where frequencies are not overlapped, are connected by cascade connection as band amplification means, and a Y-coordinate signal is obtained by a signal obtained by the third band amplification means 23 of a post-stage. Consequently, a frequency component similar to a display frame contained in signal voltage is reduced and a noise component from outside is removed. Thus highly precise coordinate detection with less jutter is realized.</p> |
