Patent ID: 8847918

Claim:
An optical position detection device comprising: a detecting light source section adapted to emit a detection light beam on a screen member having four corners; a light source drive section adapted to drive the detecting light source section to form an X-coordinate detecting light intensity distribution in which an intensity of the detection light beam varies in an X-axis direction, and a Y-coordinate detecting light intensity distribution in which an intensity of the detection light beam varies in a Y-axis direction intersecting the X-axis direction; a light detection section adapted to receive the detection light beam reflected by a target object located near the screen member; a position detection section adapted to detect a position of the target object based on a reception intensity in the light detection section; a reference light source section adapted to emit a reference light beam entering the light detection section, the light detection section detecting reception reference light intensity of the entered reference light beam; and a case adapted to contain the light detection section and the reference light source section, wherein the light detection section and the reference light source are relatively located in the case in a state in which the reference light beam emitted from the reference light source travels directly to the light detection section without reflecting at the target object so that the reception reference light intensity is constant irrespective of the position of the target object, the light detection section is located next to the detecting light source section, and the detecting light source section and the light detection section are located at one of the four corners of the screen member.