| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an optical digitizer in which the reflection efficiency of retroreflected light from a retroreflection member nearby diagonals of light sources is increased, a winder detection area for the size of the device is secured and the manufacture cost of which is suppressed. SOLUTION: The optical digitizer which detects the indication position coordinates of an indication body on a detection surface comprises the light source which emit light beams, the retroreflection member which recursively reflects the light beams emitted by the light source provided at the circumference of the detection surface, an imaging means which detects which detects the direction of a shadow formed by cutting off the retroreflected light from the retroreflection member by the indication body, an image forming lens which images the retroreflected light on the imaging means, and an incidence angle varying means which refracts the light made incident on the retroreflection member nearby the diagonals of the light sources from the light sources and varies the angle of incidence on the retroreflection member. As the incidence angle varying means, for example, a Fresnel beam splitter, etc., is usable.</p> |
