| 摘要 |
PROBLEM TO BE SOLVED: To suppress erroneous detection of detection coordinates caused by the thickness of sheets.SOLUTION: A plurality of sheets P having a position correction identifier Pm formed at a predetermined distance T3 from a reference position is held by a mounting part body 12, and ultrasonic signal issued from the ultrasonic transmission element 36 of an electronic pen 30 is received by at least two ultrasonic reception elements 18B and 18C, a trigger signal issued from the infrared emission element 34 of the electronic pen 30 at time of starting writing is received an infrared reception element 18A and, in the present state of the electronic pen 30 at the position of the position correction identifier Pm of a specific sheet P, according to a horizontal distance Lk from the ultrasonic transmission element 36 to the position correction identifier Pm determined based on a first distance Lmk and a predetermined distance Lk-T2, a plurality of position data relating to the specific sheet P is corrected by using a height Hsns calculated by the specific sheet P and the ultrasonic reception elements 18B and 18C.SELECTED DRAWING: Figure 2 |
