ELECTRONIC BLACKBOARD

摘要

PROBLEM TO BE SOLVED: To provide an electronic blackboard requiring a single pen holder alone for mounting a marker pen even when drawing on a board is carried out by means of whiteboard markers in a plurality of colors. SOLUTION: This pen holder for mounting a whiteboard marker pen transmits an infrared ray and an ultrasonic wave including color information of the marker pen. This blackboard is provided with two or more sensors receiving the infrared ray and the ultrasonic wave transmitted from the pen holder for measuring a distance to the pen holder from an arrival time difference between the infrared ray and the ultrasonic wave. The pen holder is provided with a color changing means for switching the color information according to a color of the marker pen 2a.