Eraser for electronic blackboard

摘要

An eraser for an electronic blackboard. System whose erasing area is variable according to the size and accuracy of the figure to be erased. The eraser includes a main unit carrying a small area erasing unit, and a large area erasing unit which is detachably engaged to the main unit. Detectors installed in the main unit detect when the eraser is touched on the surface of the board, and/or that the large area erasing unit is being used, and send an appropriate signal to the system controller. When the system controller receive the signal, it blanks the memories corresponding to the area covered by the erasing units and erases the corresponding area of figures displayed on the display unit.