| 摘要 |
<p>PURPOSE:To facilitate easy erasing and operation by starting automatically a partial erasion mode when a blackboard eraser touches an input surface, and executing partial erasing. CONSTITUTION:An input part of an electronic blackboard device contains the 1st and 2nd group electrode terminals 51 and 52, a partial erasion mode detecting circuit 53, a voltage detecting circuit 55, an output terminal 56, sample holding cir- cuit 61 and 63, a control signal generating circuit 56, etc. together with the 1st and 2nd parallel electrode groups 2 and 3 for detection of X and Y coordinates. Then the 3rd electrode groups Q1-QR are added newly. These 3rd electrode groups are not connected to registers 4 and 5 to which the groups 2 and 3 are connected and used for discrimination between the input and partial erasion modes. Here it is automatically discriminated whether the pressure is applied to an input surface by a writing tool like a chalk, etc. or an eraser. If a chalk is decided, the contents of the chalk are displayed on a monitor screen. While the corresponding display contents are erased in case an eraser is decided. Then an input mode is set automatically when a partial erasion mode is over.</p> |
