| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an optical digitizer where an image pickup means can sufficiently takes in reflected light even in the case that the distance between a detection unit and a retroreflection member is not sufficient in comparison with the distance between a light source and an image forming lens. SOLUTION: The optical digitizer which detects the pointed position coordinates of an indicator 2 on a detection face 1 is comprised of a light source 11 which emits light, a retroreflection member 22 which is provided in at least three sides of the periphery of the detection face 1 and retroreflects light emitted from the light source 11, the image pickup means which detects the direction of a shadow generated by interception of retroreflected light from the retroreflection member 22 by the indicator 2, and the image forming lens which forms an image of retroreflected light from the retroreflection member 22 on the image pickup means, and the light source 11 is arranged in the horizontal direction to the detection face and on the right or/and the left of the image forming lens 9 in the vicinity of the image forming lens 9.</p> |
