| 摘要 |
<p>PURPOSE:To accurately detect a position indicated by a coordinate indicator even at its peripheral part without particularly increasing the size of a coordinate detector as compared with a coordinate reading area by equalizing the intensity of electromagnetic coupling between the 1st exciting loop and detection loop with that between the 2nd exciting loop and detection loop. CONSTITUTION:When the coordinate detector 5 is apart from an exciting line 101 and the 1st and 2nd detection lines 111, 112. the intensity of electromagnetic coupling between a left exciting loop 101a and the 1st detection line 111 is equal to that between a right exiting loop 101b and the 2nd detection line 112, so that the amplitude values of both induction signals S11, S12 become equal to each other. Thereby, when a coordinate detection circuit 4a detects a difference between both the signals S11, S12, induction components generated due to direct electromagnetic coupling between the exciting lines 101 and the detection lines 111, 112 are always negated. When the indicator 5 approaches either one of exciting loops and detection lines, positional information indicated by the indicator 5 can be accurately detected.</p> |
