The optical position detection device

The optical position detection apparatus (1) for optically detecting a position in a predetermined zone (21), which is referred to by an identifier (S), said optical position detection device (1) comprises: four side frame (1a-d), wherein the lower, left and right side frames (1b-d) with a light retro-reflector (4) is provided; at least two optical transceiver units (10a, 10b) each having an optical scanning unit (11, 15) for scanning light at an angle in a plane which is parallel to the predetermined zone (21) substantially, and a light receiving unit (13) for receiving reflected light from a portion of the light retro-reflector (4) which is irradiated with the scanning light; said upper side frame (1a) at its two ends incorporating the optical transceiver units (10a, 10b); and an outer mounting member (2a, 2c, 3a, 3c, 5a-5d, 6a-6d) for mounting the light retro-reflector (4) and the optical transceiver units (10a, 10b) on a display device (20) (the predetermined zone 21 ), so that the light retro-reflector (4) and the optical transceiver units (10a, 10b) are positioned outside the predetermined zone (21); said outer mounting member (2a, 2c, 3a, 3c, 5a-5d, 6a-6d) has a changing mechanism (5a-5d, 6a-6d) for adjusting positions of the light retro-reflector (4) and the optical transceiver units (10a, 10b ), characterized in that the side frame (1a-d) each have a sliding part (6a, 6b, 6c, 6d) which is moving in one direction and guide part (5a, 5b, 5c, 5d), that the movement of the sliding part (6a, 6b, 6c , 6d) leads include, said tapered overlap portions (7b, 7c, 7d) of the light reflector (4) at the respective boundaries between the sliding parts (6b, 6c, 6d) and the guide parts (5b, 5c, 5d) are provided.