| 摘要 |
A single detector alternatively records on a current eraser position and a current pen position. A first position-sensing device (41) records the information written on a writing board (40) through a pen. A second position-sensing device (41) records the information being erased from the writing board through an eraser. - Independent claims are also included for the following: - (a) a writing board; - (b) and an electronic information representation production device. |
