Abstract: A cylindrical frame is provided with an incident angle detecting section for detecting an incident angle of the light from a source of light capable of transmitting pulses and a focus detecting section having a movable lens constructed so that it detects an incident light from the source of light to control the focus position of the incident light. On the basis of the incident angle detected by the incident angle detecting section, the movable lens is caused to be directed to the source of light. Furthermore, by the focus detecting section, the focus position of light is controlled to detect the position of the movable lens. A distance from the position to the source of light is calculated.

Abstract: A wireless input device for computer comprises a pen-type input device having a source of light capable of transmitting pulses. The wireless input device further comprises an input device body including two angle detecting section, each having a light receiving element constructed so that it is rotated to the direction of the incident angle of incident light when the incident light from the source of light is detected, and a calculating section for calculating the position of the pen-type input device from the two incident angles detected by the two angle detecting sections.