Position detection device, position pointing device, position detecting method and pen-down detecting method

摘要

A position detection device comprising a position pointer having a light reflector for reflecting light, an emitter for emitting light toward the light reflector, a light receiver for receiving light from the light reflector of the position pointer, a coordinate calculator for calculating a position coordinate of the position detecting device based on information from the light receiver. The position pointer is in the form of a pen and has a movable pen-core portion subject to displacement by the pressure on a surface of a board, a light modulator for changing characteristics of the reflection light, and a transmitter for transmitting the displacement of the pen-core portion to the light modulator. The light receiver has an up/down state detector for detecting characteristics of light changed by the light modulator and obtaining a pen-up and a pen-down information of the position pointer.